Astronomy

How dark would the sun become if we traversed a Bok globule?

How dark would the sun become if we traversed a Bok globule?



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Bart Bok gave his name to dust clouds of 2-50 solar masses, which by their darkness may be 100 times more frequent than telescopes can detect.

If the solar system traversed a Bok Globule, how dark would the sun become towards the surface of the Earth, as visible by humans?


Not noticeably darker.

Assuming such a globule has a mass of 50 solar masses and a diameter of 1 light year, that would make it's average density about $2.2 imes 10^{-16},kg,m^{-3}$ which is fairly close to not being there at all in human terms.

An imaginary tube of this stuff 1 AU tall and of area 1 meter squared would contain about $3 imes 10^{-5},kg$ of mass. That is an imaginary tube from Earth to the Sun.

That much matter won't block much light.

For comparison the density of air at ground level is about $1.2,kg,m^{-3}$. So less than a millimeter of air at ground level blocks more sunlight than the dust cloud would.

Also


Quantum Day

Star clusters are groups of stars held together by their own gravitational field. These star clusters, formerly known as star clouds, are made up of more than a hundred thousand stars that are more than a million years old.

One prominent star cluster is the Large Sagittarius Star Cloud. It is about 600 light years wide and the multitude of stars in the area makes it the "most dense concentration of individual stars visible using binoculars". Within the Large Sagittarius Star Cloud is Barnard 86. It is a cold, dark cloud of gas and dust that absorbs background light making it almost opaque to visible light. These objects are known as Bok Globules.

It is this area of the sky that is imaged above, taken by the Wide Field Imager at the La Silla Observatory in Chile.

Barnard 86 Set Against the Large Sagittarius Star Cloud

This part of the constellation of Sagittarius (The Archer) is one of the richest star fields in the whole sky -- the Large Sagittarius Star Cloud. The huge number of stars that light up this region dramatically emphasise the blackness of dark clouds like Barnard 86, which appears at the centre of this new picture from the Wide Field Imager, an instrument mounted on the MPG/ESO 2.2-metre telescope at ESO's La Silla Observatory in Chile.

This object, a small, isolated dark nebula known as a Bok globule, was described as "a drop of ink on the luminous sky" by its discoverer Edward Emerson Barnard, an American astronomer who discovered and photographed numerous comets, dark nebulae, one of Jupiter's moons, and made many other contributions. An exceptional visual observer and keen astrophotographer, Barnard was the first to use long-exposure photography to explore dark nebulae.

Through a small telescope Barnard 86 looks like a dearth of stars, or a window onto a patch of distant, clearer sky. However, this object is actually in the foreground of the star field -- a cold, dark, dense cloud made up of small dust grains that block starlight and make the region appear opaque. It is thought to have formed from the remnants of a molecular cloud that collapsed to form the nearby star cluster NGC 6520, seen just to the left of Barnard 86 in this image.

Video: Vista Survey Telescope Image of Star cluster NGC 6520 and the dark cloud Barnard 86

NGC 6520 is an open star cluster that contains many hot stars that glow bright blue-white, a telltale sign of their youth. Open clusters usually contain a few thousand stars that all formed at the same time, giving them all the same age. Such clusters usually only live comparatively short lives, on the order of several hundred million years, before drifting apart.

The incredible number of stars in this area of the sky muddles observations of this cluster, making it difficult to learn much about it. NGC 6520's age is thought to be around 150 million years, and both this star cluster and its dusty neighbour are thought to lie at a distance of around 6000 light-years from our Sun.

The stars that appear to be within Barnard 86 in the image above are in fact in front of it, lying between us and the dark cloud. Although it is not certain whether this is still happening within Barnard 86, many dark nebulae are known to have new stars forming in their centres -- as seen in the famous Horsehead Nebula, the striking object Lupus 3 and to a lesser extent in another of Barnard's discoveries, the Pipe Nebula. However, the light from the youngest stars is blocked by the surrounding dusty regions, and they can only be seen in infrared or longer-wavelength light.


Bok Globules

Yesterday I talked about how gas and dust between us and the stars can cause a reddening effect due to Rayleigh scattering. Normally this isn’t a large effect, but there are examples where this reddening effect can be significant. One such example is known as a Bok globule, seen below.

Bok globules are small, dense clouds of gas and dust, typically only about a light year across. They are thought to be dust clouds undergoing the early stages of gravitational collapse, on their way to becoming a stellar nursery. Since they are in the early stages of gravitational collapse, they haven’t formed any protostars to start generating heat. So they tend to be very cold as well as dense, meaning they don’t emit much light on their own.

Most of the time they appear dark blobs illuminated by background stars or nebulae. But in cases where light does get through, the starlight is reddened by Rayleigh scattering and absorption. You can see that effect in the image below, though in the image the effect is exaggerated with a bit of false coloring.

Since Bok globules are small, and are not gravitationally bound to other objects, they move freely through the galaxy. This means they can pass in front of more distant stars, causing them to dim and redden. For this reason, Bok globules have been proposed as an answer to one of the strange mysteries in ancient astronomy, known as the Red Sirius mystery.

Ptolemy was a second-century astronomer who wrote an authoritative book on astronomy known as the Almagest. In this book Ptolemy lists six bright red stars (Betelgeuse, Antares, Aldebaran, Arcturus, Pollux, and Sirius). Of these, the first five are decidedly red (or in the case of Pollux, red-ish). But Sirius is bluish white. So why call it red?

You might be tempted to write Ptolemy’s observation off as poor observation, but the guy was a high-calibre astronomer. There is also the fact that other prominent scholars of the time (such as Pliny the elder) also described Sirius as red.

Given what we know about stellar evolution in general, and Sirius in particular, we know that Sirius was not in a red giant stage nearly 2000 years ago. Nor was its white dwarf companion Sirius B. So either Sirius wasn’t red, and Ptolemy was incorrect in his assertion (or misquoted in subsequent manuscript copies), or something must have caused Sirius to appear red.

This is where Bok globules come in. One proposal to the Red Sirius mystery is that a Bok globule passed in between us and Sirius, making the star appear red for a few hundred years. The downside of this solution is that it would also make Sirus appear much dimmer, and even when Sirius is described as red, it is always also described as bright.

Most astronomers don’t give a lot of credence to the idea that Sirius was actually red at the time of Ptolemy. While other scholars can be seen to support his description, their specific writings can be a bit fuzzy in their interpretation. Then there is the fact that Chinese astronomers of that period (consummate observers in their own right) consistently describe Sirius as bright and white, and make no mention of any dimming or reddening.

But these small clouds have enough mysteries to hold our attention. We’re not entirely sure how they’ve gotten so dense given their size, then there is the fact that they are one of the coldest types of objects in the galaxy, and their temperature and density means that some interesting near-vacuum chemistry is going on.


Journey Inside A Bok Globule

You asked for more? You got it. This time our dimensional visualization is going to take us 9500 light years away from where you’re sitting now and deep into the Perseus spiral arm of the Milky Way Galaxy. Buckle your seat belt and relax your eyes, because we’re heading into two versions of a 132 light year expanse known as NGC 281 and the central core called IC 1590…

Just like last time, this dual image requires a little bit of a challenge on your part to create a 3D effect. Thanks to the wizardry of Jukka Metsavainio, we’ve gone even one better. There’s two! The first version you see on this page are for those of you who have success relaxing your eyes and being a certain distance from the screen to get the images to merge. The one below is for those of you who have better luck crossing your eyes and catching dimension in the center image. Are you ready for your journey? Then have a look and let’s learn…

The whole gigantic region of nebulosity is known as NGC 281 and most commonly referred to as the “Pac Man Nebula”. Visible to small telescopes and located in the constellation of Cassiopeia (RA 00:42:59.35 Dec +56:37.18.8), this cloud of high density hydrogen gas is being ionized by an incredible output of ultraviolet radiation from the hot, neophyte stars which coalesced there. Deep in the center of this HII region is a open area called IC 1590 – home to a young galactic star cluster – and several dark patches known as “Bok Globules”.

If that sounds like something you might expel when you have a cold, you’re right. They are cold… Cold pockets of dense dust, molecular hydrogen and gas. Bok globules are the brain child of astronomer Dr. Bart Jan Bok – who, among other things, loved to study the paranormal. When Bok proposed their existence in the 1940’s, he knew what was going on. These dark regions were acting like interstellar cocoons – protecting their inner stars from being stripped by the radioactive stellar winds of nearby companions and blocking visible light. When stellar metamorphosis had occurred, the new star then begins to send out its own winds and radiation to evaporate the globule – but this isn’t always the case. Sometimes the cocoon gets destroyed before the life inside ignites.

In our image you will see bright blue stars, members of the young open cluster IC 1590, near the globules. Meanwhile, the cluster’s partially revealed core in the upper right hand corner is filled with a tight grouping of extremely hot, massive stars emitting visible and ultraviolet light, causing those incredible pink clouds. When these star forming dust clouds were first imaged by Hubble, we thought we knew a lot about them. But what have we learned since?

According to research done by T.H. Henning (et al): “The exciting star HD 5005 of the optical nebulosity is a Trapezium system… and emission shows that the molecular cloud NGC 281 A consists of two cloud fragments. The western fragment is more compact and massive than the eastern fragment and contains an NH3 core. This core is associated with the IRAS source 00494+5617, an H2O maser, and 1.3 millimeter dust continuum radiation. Both cloud fragments contain altogether 22 IRAS point sources which mostly share the properties of young stellar objects. The maxima of the 60 and 100 micrometers HIRES maps correspond to the maxima of the (12)CO (3 to 2) emission. The NGC 281 A region shares many properties with the Orion Trapezium-BN/KL region the main differences being a larger separation between the cluster centroid and the new site of star formation as well as a lower mass and luminosity of the molecular cloud and the infrared cluster.”

Great! It’s confirmed! It’s a star forming region, very much like what we can observe when we see M42. But, maybe… Maybe there’s just a little bit more to it than that? Hubble observations shows the jagged structure of the dust clouds as if they are being stripped apart from the outside. What could have caused that? Only the radiation from the nearby stars? Hmmm…. Not everyone seems to think so.

A 2007 study done by Mayumi Sato (et al) states: “Our new results provide the most direct evidence that the gas in the NGC 281 region was blown out from the Galactic plane, most likely in a superbubble driven by multiple or sequential supernova explosions in the Galactic plane.” Supernova? Yeah, you bet. And someone else thinks so, too…

Says S.T. Megeath (et al): “We suggest that the ring has formed in a superbubble blowout driven by OB stars in the plane of the Galaxy. Within the cloud complex, combined optical, NIR, mm and cm data detailing the interaction of a young O star with neighboring molecular cores, provide evidence of triggered star formation inside the cloud complex on a few parsec scale. These data suggest that two modes of triggered star formation are operating in the NGC 281 complex – the initial supernovae triggered formation of the entire complex and, after the first generation of O stars formed, the subsequent triggering of star formation by photoevaporation-driven molecular core compression.”

You’ve got it. This type of research suggests the cores were created within the molecular cloud. When they were exposed to direct UV radiation, the low density gas was stripped. This increase in pressure then caused a rippling shockwave which triggered star formation – first in the compressed regions and then in the HII areas. Says Megeath, “The total kinetic energy of the ring requires the energy of multiple supernovae. Both the high Galactic latitude and large expansion velocity may be explained if the NGC 281 complex originated in the blowout of an expanding superbubble. The loop of HI seen extending from the Galactic plane may trace the edge of a superbubble powered by supernovae near the Galactic plane. The expansion of a superbubble into the increasingly rarefied Galactic atmosphere can lead to a runaway expansion of the shell and the blowout of the bubble into the Galactic atmosphere. NGC 281 could have formed in the gas swept up and compressed in a blowout. Hence, NGC 281 maybe an example of the supernovae-driven formation of molecular clouds (and consequently, supernovae-triggered star formation).”

What incredible region! Hope you enjoyed your journey… And be sure to tip your hat to Bart Jan Bok who told the IAU (when they named Asteroid Bok for him in 1983) “Thanks for a little plot of land that I can retire to and live on.”

Our many, many thanks to Jukka Metsavainio of Northern Galactic for creating this unique image for Universe Today Readers! We look forward to more…


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Meaning of globule in English:

2 Astronomy
A small dark cloud of gas and dust seen against a brighter background such as a luminous nebula.

  • &lsquoElsewhere in the Milky Way, Spitzer viewed a dark, elongated globule known as the Elephant's Trunk nebula.&rsquo
  • &lsquoOrganic globules found in a meteorite that slammed into the lake may be older than our sun, a new study says.&rsquo
  • &lsquoMost of the remaining one percent is the very component that makes Bok globules opaque - the interstellar dust.&rsquo
  • &lsquoThis convection results in the Sun's surface not being smooth, but covered with thousands of these globules, which are called granules.&rsquo
  • &lsquoWere Cygnus XR - 1 a neutron star, rather than a black hole, the pulses would have been brighter as the gas globules crashed onto the dense core, but instead they simply vanished.&rsquo

Origin

Mid 17th century from French, or from Latin globulus, diminutive of globus ‘spherical object, globe’.


The First Stars In The Universe Are Forever Invisible To Human Eyes

A view of distant stars and galaxies seen through nearby gas clouds. Image credit: ESO/M. . [+] Kornmesser.

Imagine the night sky as you know it. Far away from the cities, on a moonless night, out in the darkest areas you’ve ever experienced. Maybe you lay back on the grass, gazing up at the heavens above. You look up, the air is cool, and the sky is clear: no clouds to be seen at all. What is it that you’re likely to see?

The night sky as seen from Trysil, Norway. Image credit: flickr user Timothy Boocock, under a . [+] c.c.-by-s.a. 2.0 license.

Yes, there are planets, stars bright and dim and even the Milky Way overhead. But perhaps the most striking thing about the night sky isn’t the presence of these few, dispersed lights, but rather the fact that — at almost every location you can point — the sky itself is dark. If you think about it for a minute, it doesn’t make a whole lot of sense that this should be the case.

If the Universe were really, truly full of stars — of points of light in all directions — then you’d fully expect that wherever you looked, in any direction, eventually your line-of-sight would run smack into a star. And once that happened, you wouldn’t see “dark” anywhere you looked. Every point, eventually, would be filled with light, no matter how distant that star, galaxy or other point of light happened to be.

The core of the globular cluster Omega Centauri, which is what you'd expect the night sky to look . [+] like if there were stars everywhere. Image credit: NASA/ESA and The Hubble Heritage Team (STScI/AURA), via http://www.spacetelescope.org/images/opo0133a/.

This was one of the great paradoxes of the 19th century: Olbers’ paradox, which showed that the idea of an infinite Universe filled with an infinite number of stars spread out over that space was incompatible with the dark night sky we could all see.

The resolution to this paradox, of course, is that when we look at the distant Universe, we’re actually looking back in time, and since the Universe existed in a hot, dense, more uniform early state, there was a time before which the Universe didn’t contain any stars, since it took time for gravitation to begin collapsing that primordial gas into stars for the very first time. Look out beyond a certain distance, and you won’t ever see even a single star.

The reionization and star-formation history of our Universe. Image credit: NASA / S.G. Djorgovski & . [+] Digital Media Center / Caltech.

After the Big Bang, the Universe was hot, dense and uniform, but also expanding and cooling. By time the Universe is around 380,000 years old, it’s cooled enough to form neutral atoms for the first time. But there are two barriers to seeing anything:

  1. There’s nothing to see until we start creating something that emits light.
  2. Even once you do that, the Universe needs to become transparent.

Although these two problems — the formation of the first stars and the Universe becoming transparent — are often conflated together as “the dark ages,” they’re two separate problems that the Universe needs to solve.

The Cygnus Wall in the North American Nebula, NGC 7000. Image credit: Ken Crawford, under a . [+] c.c.a.-s.a.-4.0 international license.

First, you simply don’t have anything to see until you form stars for the first time. While the Universe started off almost perfectly uniform, there are tiny imperfections, including some regions that start off with slightly more matter than average. Over time, gravitation works to pull more and more matter into these overdense regions, growing them into clumps of matter.

It takes tens of millions of years, but after enough time passes, these clumps grow large enough that gravity begins to collapse them under their own gravity. And when the cores of these clumps of atoms and molecules get dense enough, the process of nuclear fusion — burning hydrogen fuel into helium — can finally occur!

A young, star-forming region found within our own Milky Way. Image credit: NASA, ESA, and the Hubble . [+] Heritage (STScI/AURA)-ESA/Hubble Collaboration Acknowledgment: R. O’Connell (University of Virginia) and the WFC3 Scientific Oversight Committee.

These sites of nuclear fusion become the cores of the very first stars in the Universe, burning hot and bright, and emitting the first visible light the Universe has seen since the early stages of the hot Big Bang. This happens after as little as 50 million years into the Universe’s history, an incredibly short time to the first stars. But there’s a problem: none of these stars are actually visible to us!

The dark nebula Barnard 68, now known to be a molecular cloud called a Bok globule. Image credit: . [+] ESO, via http://www.eso.org/public/images/eso0102a/.

Sure, the stars are emitting light, but so are the stars behind the “dark nebula” above, Barnard 68. This nebula appears so dark because the light from the stars is blocked! Why’s this? Because the atoms and molecules that exist in there are of the right physical size to absorb — and hence appear opaque — to visible light.

While single atoms themselves only have specific atomic transitions they can absorb light at, when they’re bound together in all sorts of intricate configurations, they can actually block the full spectrum of visible light. And this type of opacity is exactly what’s going to happen when the first stars form: the Universe might be creating light, but there’s no way for it to travel to our eyes.

So how do we get out of this?

Molecular cloud BHR 71. Image credit: J. Alves (ESO), E. Tolstoy (Groningen), R. Fosbury (ST-ECF), & . [+] R. Hook (ST-ECF), VLT.

You have to ionize those atoms! Or, more specifically, you have to reionize them, since they were ionized once before -- back before they became neutral in the first place. But this doesn’t happen quickly this is a process that requires billions upon billions of stars to form, emit ultraviolet, ionizing radiation and strike more than 99% of the neutral atoms in the Universe. It’s a gradual process, one that takes around 550 million years to complete!

But this doesn't mean it takes 550 million years before the first stars form. According to our best models of structure formation, the very first stars form only between 50-to-100 million years after the Big Bang. The very first stars formed much earlier than we've ever been able to see, and we didn’t form enough of these stars — and they didn’t burn hot enough for long enough — to reionize the Universe and make it transparent to light until 550 million years had gone by.

An illustration of the first stars turning on in the Universe. Image credit: NASA.

It’s not enough, in the Universe, to simply “let there be light” in order to see the first stars: you need for that light to be able to freely travel through space! In visible light, there’s no way to see them. No matter how good the Hubble Space Telescope ever is, no matter how long it stares at these patches of sky, it will never see back to the first stars, because the Universe is still opaque to visible light.

But there is hope, and the James Webb Space Telescope has the potential to transform our perspective from hope into reality.

The same Bok globule -- Barnard 68 -- as was shown earlier, except with a partially infrared view . [+] shown at right. Image credit: European Southern Observatory (ESO).

By looking in longer wavelengths of light, those dusty configurations of atoms and molecules might actually be transparent to those wavelengths. Even though Hubble might not be able to see those stars, James Webb, which will view infrared (and quite long infrared) wavelengths, will be able to see all the way out to epochs where the Universe was opaque to visible light.

In other words, when JWST launches in just two years, we may truly be able to probe the first stars in the Universe, not merely hundreds of millions of years after the fact, when the Universe becomes transparent to visible light. The first stars in the Universe may be invisible for a time, but that’s a fault of our eyes, not a fault of the light!


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There´s a serene aurora, both a violent Sun and an eclipsed one, a stellar nursery and a stellar graveyard, and many more superb pictures. The Astronomy Photographer of the Year 2014 winners were announced in September and you can see all of them.

Aurorae - Polar Light Shows
There's a glow on the northern horizon. The Sun set hours ago and there are no city lights there. You could be seeing nature's great polar light show - an aurora. It's most likely if you're fairly far north or south, but a solar storm may include mid-latitudes too.

Carrington Event – Biggest Solar Storm on Record
Dazzling aurorae filled the skies. Birds thought it was morning, people thought the world was ending. The telegraph didn't work. But strangely, sometimes the telegraph operators could send messages without a power supply. This was the Carrington Event, the biggest solar storm ever recorded.

Einstein´s Eclipse
While World War I was tearing Europe apart in 1915, a German physicist presented a theory that would shake up the way we see the Universe. The physicist was Albert Einstein, his face still unknown to the world, his name not yet a synonym for genius. How did a solar eclipse in 1919 change all that?

Four Historic Eclipses
An empire lost, an empire saved, lives lost, lives saved. Read about some unexpected outcomes of solar and lunar eclipses.

Galactic Winter Games
Welcome to the Galactic Winter Games, a starry tribute to Earth´s Winter Olympic Games. It´s a tour of some really cool cosmic sights – as well as some hot ones, such as one of the biggest explosions in the Universe.

How the Sun Was Born – Facts for Kids
The Sun didn´t exist five billion years ago. But the material to make it did. There was even enough to make a number of stars and still have material left over for planets, moons and other small bodies. What was this material, and how did it end up as stars and planets?

How the Sun Will Die - Facts for Kids
The Sun was born in a nebula five billion years ago. It´s going to keep going for another few billion years, but it won´t last forever. Here´s the story of what happens to a sunlike star when it runs out of fuel. And some of it is very strange.

Hurtigruten - Seeing the Northern Lights
What would it be like to take an astronomy tour on the Hurtigruten? Here is an account of some of the highlights of a trip around the coast of Norway in search of the northern lights. We heard stories of the constellations and then found them in the sky. And one night we saw the aurora dancing.

Kew Observatory
An observatory that a king built to watch the 1769 transit of Venus. The place where official time for London used to be set. Where a murderer was sometimes in attendance when the King walked in the gardens. Find out about the history of Kew Observatory.

Life and Death of the Sun
In the distant future the Sun will be many times its present size and thousands of times brighter. It will seed the Galaxy with elements like carbon and oxygen–perhaps for life on a world yet unborn. Then it will collapse into a tiny dead sphere. For a time, a beautiful nebula will mark its place.

Northern Lights Planetarium
Tromso, far to the north of Norway, attracts summer visitors to see the midnight sun and winter visitors to see the aurora borealis. The Northern Lights Planetarium is the northernmost planetarium in the world. It´s worth a visit at anytime, but extra welcome if it´s too cloudy to see the sky.

Our Explosive Sun - book review
The Sun is the star of the Solar System and makes life on Earth possible. But it's also a danger to our technological civilization. Learn all about our fascinating star in the beautifully illustrated “Our Explosive Sun.”

Saint Patrick´s Day – Wearing the Cosmic Green
Saint Patrick´s Day is associated with the shamrock and the color green. Although there don´t seem to be any cosmic shamrocks, there are many green phenomena in the skies. Discover a beautiful green nebula, what excites electrons and why con men sold “comet pills”.

Solar Eclipses
Is it an ill omen, an amazing or terrifying experience, or a great opportunity for scientists? Solar eclipses have been all of these things and more. Read on to find out what it´s all about.

Tales of the Northern Lights
The aurora is an ethereal, shifting light in the northern sky and is associated with many tales and beliefs. It can look like the dawn, so Galileo named it after Aurora goddess of the dawn. It has reminded others of dragons, spirits, dancers, shield maidens, herrings or the legendary fire fox.

Teaching Why We Have Day and Night
Why do we have day and night? For thousands of years most people thought it was because the Sun went around the Earth. That is certainly what it looks like, so how can you explain that day and night happen because the earth spins on its axis? Here are some ideas.

The Sun - Facts for Kids
The Sun is a star and it´s a big one. It´s bigger than 90% of the other stars in the Milky Way and contains almost all of the mass of the whole Solar System. Find out more about the star that makes life on Earth possible.

Top Astronomy Stories 2012
What were the big astronomy stories of the year 2012? Here is my choice of the top ten plus a non-story. What do you think?

Top Ten Astronomy Stories of 2013
What were the big astronomy events of 2013? Here are my top ten choices and they include a big bang over Russia, a Moon goddess and Jade Rabbit, a telescope in the high Andean desert to look for the first galaxies and the launch one of the most ambitious space missions ever.

Voyager 1 – the First Starship
Has Voyager 1 finally left the Solar System? No, that won´t happen for tens of thousands of years. But it has left the bubble that the solar wind makes in space. The spacecraft is in the space between the stars, moving through a plasma made from ancient supernova explosions.

What Is Space Weather
Everybody knows what weather is - sun, rain, wind, cloud, etc. Although there's no atmosphere in space, space weather can endanger astronauts, and in our technological world, a severe solar storm could affect everybody. So what is space weather?

Why planets have seasons
For people living outside the tropics, June 21st is the longest or shortest day of the year, a solstice. It marks the first day of summer in the northern hemisphere and winter in the southern hemisphere. But why do we have seasons? And do other planets have them?

Content copyright © 2018 by . All rights reserved.
This content was written by . If you wish to use this content in any manner, you need written permission. Contact Mona Evans for details.


How dark would the sun become if we traversed a Bok globule? - Astronomy

The life histories of stars from birth in nebula, through the main part of their lives (the main sequence) and on to the end, possibly as a white dwarf or in a supernova explosion.

ABC of Astronomy – B Is for Bok Globule
B is for Bok globule, a kind of dark nebula studied by Bart Bok. B is for Bayer who invented a handy system of star designations beginning with a Greek letter. And B is for Baily´s beads. You won´t find them in a jewelry shop, but you might see them in a solar eclipse, as Francis Baily did.

Astronomy Humor
Here’s a collection of astronomy jokes for kids, adults and geeks of all ages. Laughter helps to keep us young and healthy, so see if anything tickles your fancy. (And how *does* the Man in the Moon cut his hair?)

Bang! - The Universe Verse - book review
What would it take to explain the Big Bang Theory? James Lu Dunbar´s "Bang!" might do it - and amuse you and your children at the same time. It´s a splendid little book which tells the story of the universe in verse and appealing graphics.

Chemical Cosmos - book review
"The Chemical Cosmos: A Guided Tour" is an astronomy book about chemistry - or perhaps a chemistry book about astronomy. It´s an engrossing guided tour that will take you from the baby Universe through the first stars, the formation of solar systems and to our search for the origins of life.

Cosmic 4th of July
What links the USA´s Independence Day holiday, the Crab Nebula and NASA´s Deep Impact spacecraft? What links the American War of Independence with the planet Uranus? And what is the Fireworks Galaxy? Read on to find out.

Cosmic Collisions
We no longer see the heavens as perfect and the stars as eternal and unchanging. Even the Universe had a beginning, and everything that we observe changes and evolves. Many of these changes involve cosmic collisions.

Cosmic Ghosts, Ghouls and Vampires
Astronomers use colorful language for cosmic objects. But unlike ghosts, ghouls and vampires in horror stories, the cosmic ones aren´t scary late at night. Here are tales of the birth, evolution and death of stars, a blinking demon and a star that, at Halloween, seems like the Sun´s ghost.

Cosmic White Christmas
If you´re dreaming of a white Christmas, the cosmos may have something of interest. How about deep snow on one of Saturn´s moons, a gigantic Christmas tree whose lights are baby stars, a snowman on an asteroid or an Einstein ring?

Creepy Crawlies in Space
What was the first Earth creature to go into space? Not a dog, but a fruit fly. Insects and arachnids have been mini-astronauts for over sixty years. They have also inspired the naming of heavenly objects.

Death of a Massive Star
Massive stars are born in the same way as smaller stars like the Sun. But a massive star then burns brighter and hotter, and ends its life in one of the Universe's most stupendous explosions, a supernova. For a time, it shines as bright as entire galaxy of a billion stars.

Do Red Dwarfs Live Forever
Looking up at a clear, dark sky, you can see thousands of stars. Yet without binoculars or a telescope, the most common type of star is invisible. These are the small, cool red dwarfs that fill the sky and live practically forever.

Empire of the Stars - Book Review
A fateful meeting of the Royal Astronomical Society in London adversely affected the lives of two scientists and hindered progress in the study of black holes for a half a century. So says the author of Empire of the Stars. BellaOnline´s astronomy editor liked the book, but wasn´t convinced.

Galactic Winter Games
Welcome to the Galactic Winter Games, a starry tribute to Earth´s Winter Olympic Games. It´s a tour of some really cool cosmic sights – as well as some hot ones, such as one of the biggest explosions in the Universe.

Gemini - the Celestial Twins
Gemini. A story of the love and loyalty of two brothers parted only by death. Includes a star that´s actually a system of six stars, and a giant star that can help us measure distances in space. Contains an object that completely baffled astronomers for twenty years.

George´s Secret Key to the Universe - book review
In Lucy & Stephen Hawking´s book, the hero George used to have a quiet life, but now he´s trying to rescue his next door neighbor from a black hole. Here´s a lively illustrated story, beautiful color images of the universe, and from the man who knows, a great explanation of what a black hole is.

Halloween
Halloween falls midway between an equinox and a solstice. In the ancient Celtic world it was new year´s eve and the start of winter - time to prepare for survival in the darkening days. But also a time when the boundary between our world and the otherworld weakened. Who knew what might cross it?

How the Sun Was Born – Facts for Kids
The Sun didn´t exist five billion years ago. But the material to make it did. There was even enough to make a number of stars and still have material left over for planets, moons and other small bodies. What was this material, and how did it end up as stars and planets?

How the Sun Will Die - Facts for Kids
The Sun was born in a nebula five billion years ago. It´s going to keep going for another few billion years, but it won´t last forever. Here´s the story of what happens to a sunlike star when it runs out of fuel. And some of it is very strange.

Icarus at the Edge of Time book review
Icarus flew too close to the Sun with wings of wood and wax. The wax melted and he fell to his death. Brian Greene´s Icarus of the future flies too close to a black hole and finds that he should have paid more attention to Einstein.

It´s Alive - book review
The Universe Verse is back. Book 1 was the Big Bang Theory in verse and drawings. Now stars and planets have formed, but something new is happening: Life. Book 2 is about evolution by natural selection. In its cheerful verse and lovely color drawings, it´s also a love poem to our beautiful Earth.

Life and Death of Massive Stars – Facts for Kids
Stars are all born in the same way, but they live and die in different ways. A star´s mass rules how hot it will be, how long it will shine, and how it will end.

Life and Death of the Sun
In the distant future the Sun will be many times its present size and thousands of times brighter. It will seed the Galaxy with elements like carbon and oxygen–perhaps for life on a world yet unborn. Then it will collapse into a tiny dead sphere. For a time, a beautiful nebula will mark its place.

Mother´s Day - An Astronomy Bouquet
Flowers from the florist are popular for Mother´s Day. But for really stellar mothers, here is a cosmic floral tribute with links to some dazzling astronomical images.

Nebulae
Nebulae are vast clouds of gas and dust between the stars. Some are stellar nurseries, others are remnants of dead stars.

Perseus the Hero
Perseus was a first-class hero: a demi-god, monster-slayer, maiden-rescuer, founder of Mycenae. When he died the gods put him in the sky. His constellation contains beautiful nebulae, a demon and a singing black hole.

Red Dwarfs - Ten Facts for Kids
If you go outside on a clear dark night, you might see a few thousand stars. But without a telescope, not a single one will be the most common type of star in the Universe. You won´t see red dwarfs, the stars that will still be shining in the far distant future when all the others have died.

Smallest Star in the Universe
No one could possibly say that a star is the smallest one in the whole Universe. But the smallest known star is 2MASS J05233822-1403022, which is a pretty big name for a star that´s about the size of Saturn. Could there be even smaller ones as yet unknown?

Starbirth
People once thought that stars were eternal and unchanging. Today we know that they have life cycles of birth and death. Here is the story of how a star like our Sun is born.

Stars – Ten Facts for Kids
Stars are nuclear reactors. If a really big one took the Sun´s place, it would swallow up the Sun and everything as far away as Jupiter. Yet others aren´t much bigger than Jupiter. Big stars don´t live very long and die in a blaze of glory. Smaller ones live for billions of years.

The Magic Furnace - book review
What is everything made of? What makes the Sun shine? "The Magic Furnace" relates the tale of how science answered these questions. The book tells a good detective story with great characters, and clues include the Big Bang and the biggest explosions in the universe.

What Herschel Found in a Dark Nebula
What´s hiding within an impenetrable dark cloud in the constellation of the Eagle? A stunning stellar nursery. Find out how the Herschel Space Observatory was able to photograph it.

White Dwarfs
White dwarfs are the corpses of medium-sized stars that have run out of fuel. They typically have the mass of the Sun, while being about the size of the Earth. It's no wonder that early twentieth century astronomers were dumbfounded by them.

Who Let the Dogs out?
Someone must have left the door open, because the skies are full of dogs. You can see the dogs of Orion and the hunting dogs of the shepherd Bootes in pursuit of the Great Bear. There is also the Running Dog Nebula and the memory of poor Laika, the first cosmonaut, who perished in space.

Young Astronomers at Work
Telescopes are essential for astronomy, but you don´t need one of your own. A computer can be the right instrument. Big telescopes collect data faster than professionals can process it, so amateurs can help. There is also room for individual ingenuity. See what some young astronomers have done.

Content copyright © 2018 by . All rights reserved.
This content was written by . If you wish to use this content in any manner, you need written permission. Contact Mona Evans for details.


How dark would the sun become if we traversed a Bok globule? - Astronomy

Astronomy doesn´t just happen. People do it. And sometimes rather than use robot probes, people also explore space. Here the stories of some of those people, both past and present.

ABC of Astronomy - B Is for Bok Globule
B is for Bok globule, a kind of dark nebula studied by Bart Bok. B is for Bayer who invented a handy system of star designations beginning with Greek letters. And B is for Baily's beads. You won't find them in a jewelry shop, but you might see them in a solar eclipse, as Francis Baily did.

ABC of Astronomy – B Is for Bok Globule
B is for Bok globule, a kind of dark nebula studied by Bart Bok. B is for Bayer who invented a handy system of star designations beginning with a Greek letter. And B is for Baily´s beads. You won´t find them in a jewelry shop, but you might see them in a solar eclipse, as Francis Baily did.

Annie Jump Cannon
Oh! Be a fine girl (guy)--kiss me! This is the traditional mnemonic for the way stars are classified: OBAFGKM. Find out about the astronomer and suffragette who devised the system and who said that astronomical spectroscopy made it "almost as if the distant stars had acquired speech."

Antonia Maury
The women of Harvard Observatory worked hard for their meager wages. And the director wanted data processed, not theoretical work. Yet some of them made significant discoveries. One of the least known, but considered by some professional astronomers to be the most able, was Antonia Maury.

Astrofest 2012
Astrofest 2012: "The Universe under one roof." Experts told us about aurorae and solar storms, dark matter and the beginning of the Universe, plus some brand new photos of the Moon. There were telescopes galore, books, an unusual demonstration of spectroscopy and many other delights.

Astrofest 2013
European Astrofest came of age in 2013, celebrating its 21st birthday. It was a memorable anniversary with a fantastic selection of speakers at sold-out lectures, busy exhibition stands, enthusiastic visitors, happy meetings and some sad farewells.

Astrofest 2014
“The Universe comes to London,” read the banner on the courtyard wall of the Kensington Conference and Events Centre. Images of the Universe, people who study it, ideas about how it works, and equipment for seeing it occupied the center for the two days of European Astrofest 2014.

Astronomers on the Mountain Tops
Big telescopes on high mountains, drawing astronomers to some exotic-sounding places. Is it as glamorous as it sounds? Not really, says one astronomer who describes some of the symptoms people suffer at high altitudes.

Astronomy Day - Bringing Astronomy to the People
Astronomy Day has been an annual celebration of astronomy for over thirty-five years of "bringing astronomy to the people." See if you can find an event near you. If not, create your own event by skywatching with a friend - our Absolute Beginners guides will help you out.

Astronomy Tributes to David Bowie
If astronomers talk about the death of stars, it's probably not pop stars they mean. Unless the pop star created Ziggy Stardust, Major Tom and Aladdin Sane, and sang “Life on Mars”, “Starman” and “Hallo Spaceboy”. Here are some of the astronomy tributes to David Bowie.

Astronomy – Why?
Astronomy is an ancient science, and today a popular profession and pastime. But what attracts people to astronomy? What´s special about it? Here are some answers to this question in the words of astronomers through the ages.

Beagle 2 – Lost and Found
On Christmas day 2003 a British-European space probe called Beagle 2 was lost on Mars and never heard from. It was not only small, but possibly broken and scattered while attempting to land. Since Mars is quite big, it took eleven years to find the little lander, and there were some surprises.

Bode and Bode´s Law
Johann Elert Bode, the author of the greatest star atlas of the Golden Age of star atlases, is better known today for Bode´s Law. Strangely, Bode´s Law is neither a law nor original to Bode. So what was it? How did it inspire the Celestial Police? How did Neptune ruin it all?

Caroline Herschel
Caroline Herschel was an intelligent young woman trapped in domestic servitude by her mother. Her brother William rescued her and trained her as a singer. After he discovered the planet Uranus, the two of them ended up forming a great partnership whose work revolutionized the study of astronomy.

Carrington Event – Biggest Solar Storm on Record
Dazzling aurorae filled the skies. Birds thought it was morning, people thought the world was ending. The telegraph didn´t work. But strangely, sometimes the telegraph operators could send messages without a power supply. This was the Carrington Event, the biggest solar storm ever recorded.

Carrying the Fire - Book Review
What was it like to be one-third of the Apollo 11 crew? Michael Collins, the man in the command module that didn't land on the Moon, tells a fascinating story of astronaut training and space travel.

Carrying the Fire - Book Review
What was it like to be one-third of the Apollo 11 crew? Michael Collins, the man in the command module that didn´t land on the Moon, tells a fascinating story of astronaut training and space travel. Originally published in 1974, a Fortieth Anniversary edition of Carrying the Fire was issued.

Cats in the Sky
There are three constellations named for dogs, but what about cats in the sky? There is astrocat Felicette who went into space and returned safely to Earth, but also constellations of big cats and a pawprint 50 light years across.

Cecilia Payne-Gaposchkin
How does the composition of a star affect the temperature? In 1925 a young woman solved this puzzle in her doctoral thesis. Her analysis was a great breakthrough in astrophysics. Otto Struve described it as “the most brilliant Ph.D. thesis ever written in astronomy.”

Ceres Facts for Kids
Bode´s Law predicted a planet between Mars and Jupiter. The Sky Police were looking for it, but Giuseppe Piazzi found it. Then someone found another one. And another one. We know of hundreds of thousands of asteroids now. Discover Ceres - planet, asteroid and dwarf planet.

Chemical Cosmos - book review
"The Chemical Cosmos: A Guided Tour" is an astronomy book about chemistry - or perhaps a chemistry book about astronomy. It´s an engrossing guided tour that will take you from the baby Universe through the first stars, the formation of solar systems and to our search for the origins of life.

Christmas in the Skies
Christmas is a special day with a magic of its own. A Christmas eclipse is a great treat and centuries ago a long-awaited comet finally showed up on Christmas day. On the other hand, imagine spending the holidays a quarter of a million miles from home as the crew of Apollo 8 did.

Columbus and the Flat Earth Myth
Doesn't everyone know that in the 15th century people thought the Earth was flat? And that brave Christopher Columbus sailed westward from Spain to get to Asia to show that the Earth was round? Once I'd have answered “Yes” to both of these questions, but it turns out that they are myths.

Copernicus - His Life
The day job of Nicolaus Copernicus, the reluctant revolutionary, was canon of a cathedral. The last resting place of this man who turned astronomy on its head was unmarked. How did his student astronomy books help to identify his remains four and a half centuries after his death?

Copernicus - the Revolution
In the 16th century everyone knew that Earth was the center of the cosmos. But this made it impossible to predict the motions of heavenly bodies, even if they moved in elaborate circles within circles. Copernicus turned the idea on its head and put the Sun at the center. A revolution had begun!

Copernicus - the Revolution
In the 16th century everyone knew that Earth was the center of the cosmos. But this made it impossible to predict the motions of heavenly bodies, even if they moved in elaborate circles within circles. Copernicus turned the idea on its head and put the Sun at the center. A revolution had begun!

Copernicus for Kids
Since the name of Nicolaus Copernicus is still well known nearly five hundred years after his death, why was his grave unmarked until 2010? Find out about the life of the quiet revolutionary that turned our view of the universe inside out.

Cosmic 4th of July
What links the USA´s Independence Day holiday, the Crab Nebula and NASA´s Deep Impact spacecraft? What links the American War of Independence with the planet Uranus? And what is the Fireworks Galaxy? Read on to find out.

Dark Matter - Poems of Space - book review
What do poets see when they look at the heavens? And astronomers? Are the experiences completely different or different sides of the same sense of wonder? This collection of poems, edited by a poet and an astrophysicist, is a treasure trove. There´s something here for everyone.

Dark Universe - film review
How did space and time begin? How did the Universe evolve? Why is the Universe dark? The "Dark Universe" planetarium show looks at these questions, and how science got some of the answers. It´s informative, up-to-date, and tells the story with stunning imagery and Neil deGrasse Tyson´s narration.

Doodles for Women Astronomers
Four outstanding women astronomers were honored by a Google Doodle in recent years. None of the Doodles have had a worldwide reach, but there is a link to each delightful drawing and I've given some biographical details. Read on to meet this stellar quartet.

Edmond Halley
Halley didn't discover a comet, but he did research and published papers in astronomy and many other fields. Russian Czar Peter the Great liked him as a dining and drinking companion and King William III put this civilian in charge of a Royal Navy ship. But how did he get a comet named for him?

Edward Charles Pickering
Edward Pickering was a leading light of 19th century astronomy who made the Harvard College Observatory into an institution with an international reputation. He was honored for his work by scientific societies in several countries, but his name is now known from his employing “Pickering's harem”.

Einstein's Eclipse
While World War I was tearing Europe apart in 1915, a German physicist presented a theory that would shake up the way we see the Universe. The physicist was Albert Einstein, his face still unknown to the world, his name not yet a synonym for genius. How did a solar eclipse in 1919 change all that?

Einstein´s Eclipse
While World War I was tearing Europe apart in 1915, a German physicist presented a theory that would shake up the way we see the Universe. The physicist was Albert Einstein, his face still unknown to the world, his name not yet a synonym for genius. How did a solar eclipse in 1919 change all that?

Empire of the Stars - book review
A fateful meeting of the Royal Astronomical Society in London adversely affected the lives of two scientists and hindered progress in the study of black holes for a half a century. So says the author of Empire of the Stars. Liked the book, but wasn´t convinced.

European Astrofest 2016
It's great to have access to “the Universe under one roof”. When European Astrofest comes to the Kensington Conference Centre in London, it saves many light years of travel. Here are some highlights of the 2016 event.

European Astrofest 2017
It was the 25th Astrofest – and how things have changed since the first one! No one knew then if other stars had planets. Pluto was still a planet and its discoverer Clyde Tombaugh was still alive. The Rosetta mission was in the very early planning stages, and Cassini-Huygens hadn't been launched.

European AstroFest 2018 - Astronomy Potpourri
European AstroFest 2018, billed as "The Universe under One Roof", was held in the Kensington Conference and Events Centre in London. The conference program included talks on dark matter, gravitational waves, asteroid impacts and wintering in White Mars.

European AstroFest 2018 - Space Missions
For two days there was no need for a telescope to view the Universe, though you might have decided to buy one for later on. The Universe came to London in the form of European AstroFest – all under one roof in the Kensington Conference and Events Centre. Here is Part 1 of some highlights.

Father Hell - Astronomer
The Moon's Hell crater sounds like the last place a space tourist would ever want to visit. But it's named for 18th century astronomer Father Maximilian Hell, director of the Vienna Observatory. He observed the 1769 Venus transit from Norway's far north, surviving the cold by adopting Sami dress.

First Orbit - film
On April 12, 1961 Yuri Gagarin saw what no human had ever seen before: the Earth from space. "First Orbit" allows you to imagine that you are making the historic voyage. Film shot from the International Space Station creates the views, but you'll also have Philip Sheppard's music.

First Orbit - film review
On April 12, 1961 Yuri Gagarin saw what no human had ever seen before: the Earth from space. Now "First Orbit" allows you to imagine that you are making the historic voyage. Film shot from the International Space Station creates the views, but you´ll also have Philip Sheppard´s music.

Galileo´s Daughter - book review
Most people think of Galileo as the man who is a symbol of the heroic voice of truth against a powerful reactionary Church. However this mythic Galileo is not the one Dava Sobel´s book, "Galileo´s Daughter", reveals through his faith, his work and his daughter´s love.

Henrietta Swan Leavitt
Henrietta Leavitt isn't a well known name, but a century ago she made one of the most important discoveries of 20th century astronomy. Previously, astronomers could only measure distances up to 100 light years, but her work extended that to 10 million light years.

Heroes of the Revolution - Doodles
For umpteen centuries people thought the Earth was the center of the cosmos. In the 2nd century AD, this view was the foundation for Ptolemy's Almagest and it persisted into the 18th century. But it wasn't unchallenged, there was a revolution in the making.

Herschel Museum of Astronomy
In 1781 William Herschel was the first person in history to discover a new planet. He was observing in the back garden of his home in Bath, England. The house where history was made is a museum and its new Caroline Lucretia Gallery is named for William´s sister, the first woman to discover a comet.

Herschel Partnership - for Kids
The Herschels were the greatest astronomical family of all time. A partnership of two brothers and a sister built the best telescopes of their time, and with those telescopes mapped the deep sky. They changed the way astronomers understood the heavens.

In the Shadow of the Moon - film
What would it be like to leave Earth's protective embrace and journey to an alien world? Only twenty-four men have ever experienced this - Apollo astronauts. "In the Shadow of the Moon" uses original footage & astronaut interviews to tell the story of one of the defining events of human history.

In the Shadow of the Moon - film review
What would it be like to leave Earth´s protective embrace and journey to an alien world? Only twenty-four men have ever experienced this - Apollo astronauts. "In the Shadow of the Moon" uses original footage & astronaut interviews to tell the story of one of the defining events of human history.

Isaac Newton - His Life
Isaac Newton's thinking about gravitation really was stimulated by seeing an apple fall, but not on his head! Find out more about the troubled child and and indifferent school pupil who became a dominant figure in science, and still is nearly three hundred years after his death.

Jean-Dominique Cassini
The Cassini Mission to Saturn is one of NASA's best known undertakings. For over fourteen years it sent images and data back from the ringed planet and its moons. But who was the Cassini that gave his name to the spacecraft?

Johannes Hevelius
Which 17th century brewer created ten new constellations? Johannes Hevelius, astronomer, civic leader, instrument-maker, writer, engraver and publisher. He died before finishing his great star atlas, so his wife Elisabetha - also an astronomer - finished the editing and oversaw its publication.

Johannes Kepler - His Life
Johannes Kepler gave the first accurate description of the Solar System. As he did his work, he struggled with poverty, insecurity and bereavement in troubled times. Religion and warfare were tearing Europe apart, but Kepler never gave up his quest to understand the cosmos.

John Herschel
John Herschel was the son of William Herschel, discoverer of the planet Uranus. But he earned his own reputation as an astronomer, mathematician, chemist, translator, artist, writer, and pioneer of photography. When he died he was laid to rest in Westminster Abbey near Sir Isaac Newton.

John Herschel – Facts for Kids
It can be hard to be the son of a famous man. Although his father was the first person in history to discover a planet, John Herschel had his own illustrious career. He was not only an astronomer, but also a brilliant mathematician, a talented artist, musician and poet, and a loving family man.

Lacaille´s skies – Arts
Much of the southern sky wasn´t visible to the ancient Mediterranean civilizations. Instead of representing the ancient myths, the constellations were invented long afterwards by European explorers and astronomers. Some of Abbe Lacaille´s inventions are tributes to the arts.

Lacaille´s skies – Sciences
There´s a curious set of constellations in the southern skies. They don´t represent exotic animals, heroic deeds or the foibles of ancient deities. They´re composed of dim and nameless stars. Find out why Abbe Lacaille invented them, and take a quick tour.

Le Gentil - Heroic Failure
Here's the story of Guillaume Le Gentil who went to India to observe the transit of Venus in 1761 and took eleven years to get home again. War and weather conspired to prevent his making observations and illness further delayed his return. Was he the unluckiest astronomer ever?

Maria Mitchell
Maria Mitchell was a true pioneer woman. She didn't brave a physical wilderness. Hers was the harder job of pioneering higher education for women. She was the first American woman to discover a comet, the first to be elected to scientific societies and the first woman professor of astronomy.

Mary Somerville and the World of Science – book
Mary Somerville was an exceptional individual. Although self-educated and - as a woman - barred from membership in scientific societies, her books sold well and were used as textbooks for many decades. Allan Chapman relates her achievements to the context of 19th century science in Britain.

Mary Somerville and the World of Science – book
Mary Somerville was an exceptional individual. Although self-educated and - as a woman - barred from membership in scientific societies, her books sold well and were used as textbooks for many decades. Allan Chapman relates her achievements to the context of 19th century science in Britain.

Miss Leavitt's Stars - book review
In the early 20th century an astronomer made a revolutionary discovery. Yet her life left almost no footprints on history. "Miss Leavitt's Stars" contrasts the solidity of her professional accomplishment with the butterfly touch of her life. Miss Leavitt isn't even the star of her own biography.

Miss Leavitt´s Stars - book review
In the early 20th century an astronomer made a revolutionary discovery. Yet her life left almost no footprints on history. "Miss Leavitt´s Stars" contrasts the solidity of her professional accomplishment with the butterfly touch of her life. Miss Leavitt isn´t even the star of her own biography.

NASA Women in Lego
Achievements may be honored with prizes and medals, but few get represented as children's toys. However Lego responded to a proposal to showcase women in space and astronomy by making a Lego set representing four such women and their major contributions. Who were these women?

Nicolas-Louis de Lacaille
Nicolas-Louis de Lacaille (1713-1762) was one of astronomy's greats. He surveyed nearly 10,000 stars in the southern hemisphere and invented fourteen new constellations still in use today. He was always thoughtful in dealing with others, but he really preferred the stars to people.

Packing for Mars - book review
If you think being an astronaut is a glamorous occupation, Mary Roach's book “Packing for Mars” will bring you down to Earth. Playing in free-fall looks like fun, but without gravity, eating, hygiene and dealing with waste are not fun. Here's the lowdown. Still want to go to Mars?

Phantom Planets and Moons
Moons of Venus and Mercury? An unknown planet nearer the Sun than Mercury? Astronomers can misinterpret what they see, too. Happily, other observers, better instruments and new theoretical understandings can put it right. Here are some phantom objects that many astronomers once thought existed.

Robert Hooke - England's Leonardo
In the 17th century Robert Hooke produced a revolutionary bestseller, helped rebuild London after the Great Fire, and was a renowned experimenter, inventor, musician and artist. Hooke contributed to astronomy, geology, structural engineering and chemistry. He was 'England's Leonardo'.

Seeing in the Dark - book review
Does amateur equal incompetence? No, says Timothy Ferris in a superb book exploring the role of amateur astronomers in probing the heavens. He reminds us that the root of the word amateur is love, and interweaves the stories of these lovers of astronomy with a grand tour of the universe.

Syon House
The Wizard Earl, the start of astronomy with a telescope, Sir Walter Raleigh, Virginia, the Gunpowder Plot, and the Smithsonian. What does all of this history have in common? Syon Park, a stately home on the River Thames.

Syon House
What is the thread that unites: the Wizard Earl, the first recorded use of an astronomical telescope, Sir Walter Raleigh, Virginia, the Gunpowder Plot, and the Smithsonian? Syon Park, a historic estate on the River Thames in England.

The Transit of Venus - book review
In the north of England in the early 17th century, there was an amazing circle of astronomers. They were well ahead of their time and included the first two people ever to observe a transit of Venus. What ended this brief flowering? Peter Aughton tells the story.

Top Astronomy Stories 2012
What were the big astronomy stories of the year 2012? Here is my choice of the top ten plus a non-story. What do you think?

Tycho Brahe
One of the greatest astronomers of all time was a Danish nobleman with a metal nose, who was also a publisher, an alchemist and the Imperial Mathematician. His astronomical observations were the key to the modern view of the Solar System.

Valentina Tereshkova - the First Spacewoman
Three days orbiting Earth strapped into a space capsule so primitive that no one could land in it. So how did the cosmonaut get home? That's part of the story of the first woman in space, on a solo flight twenty years before NASA sent Sally Ride into orbit on a Space Shuttle.

What Herschel Found in a Dark Cloud
What´s hiding within an impenetrable dark cloud in the constellation of the Eagle? A stunning stellar nursery. Find out how the Herschel Space Observatory was able to photograph it.

What Is Hanny's Voorwerp
Hanny's Voorwerp was first seen in 2007 - a strange blue blob in the constellation of Leo Minor. Since then it has been imaged by large telescopes in visible light, ultraviolet light, infrared light, radio waves and x-rays, but astronomers still don't entirely agree about the mystery object.

What´s in a Name
Things aren´t always what they seem. Many discoveries aren´t named for – or by – their discoverers. Halley didn´t discover Comet Halley. Kuiper said the Kuiper Belt didn´t exist. The Herschels called Uranus "the Georgian planet" after George III of England, but no one else did.

William Herschel
A professional musician named William Herschel was the first person in history to discover a planet. Later, as a professional astronomer, Herschel studied the stars and deep space objects to try to understand “the construction of the heavens.” He was one of the fathers of modern astronomy.

Williamina Fleming
Through the vision and dedication of Edward Pickering, Harvard College had one of the world's top observatories. Pickering had a secret weapon: a team of women computers. One of them was Mina Fleming who began her employment as a housekeeper and ended it as an astronomer of international repute.

Young Astronomers at Work
Telescopes are essential for astronomy, but you don't need one of your own. A computer can be the right instrument. Big telescopes collect data faster than professionals can process it, so amateurs can help. There is also room for individual ingenuity. See what some young astronomers have done.

Young Astronomers Reveal the Universe
In the film Deep Impact a teenage astronomer discovers a comet with a small telescope. In reality, teenage astronomers are more likely to make their discoveries in front of a computer - finding supernovae, pulsars, asteroids. The youngest discoverer was ten. Let them inspire you.

Yuri Gagarin – The First Spaceman
There was no fanfare or countdown when Yuri Gagarin became the first human to orbit the Earth. On April 12, 1961, Vostok 1 blasted off with a “Let's go!”. Gagarin was an exceptional individual who came from humble beginnings, and at 34 his life ended all too soon.

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