Category: Hubble

Ahh, another beautiful photograph captured by the Hubble Space Telescope. This time we’re looking at two big, beautiful spiral galaxies… tearing each other apart. The large, face-on spiral is NGC 3808, while its dueling partner is the smaller, edge-on NGC 3808A. And between the two is a long today tail of stars, gas and dust, transferring from one to the other.

The two galaxies are collectively known as Arp 87; just one of the hundreds of interacting galaxies seen by astronomers. It was cataloged by the famous Halton Arp in the 1960’s, who maintained his Atlas of Peculiar Galaxies. And this collision is plenty peculiar, thanks to Hubble’s optics and resolution of fine details.

A stream of gas, stars and dust is flowing from NGC 3808 to its companion, enveloping it in a starry embrace. Because the NGC 3808A is seen nearly edge-on, you can make out the twisting trail of stars wrapping around it. Both galaxies have been distorted by their gravitational interaction.

When galaxies interact, stars are born. And this is the case for Arp 87. The colour of the stars and the intensity of heated interstellar dust show that both galaxies are undergoing furious rates of star formation.

Original Source: Hubble News Release

Look at the picture associated with this story. It just looks like a pretty galaxy, right? Well, according to astronomers, it’s actually much older than it appears. This image, captured by the Hubble Space Telescope, provides one of the most detailed observations ever taken of I Zwicky 18 – a galaxy that looks younger than it should.

According to researcher, galaxies like I Zwicky 18 are much more common billions of light years away, at a time when the Universe was much younger than it is today. These baby galaxies still had large quantities of gas and dust they could use up to make new stars. Their young hot stars, composed largely of primordial hydrogen and helium manufactured during the Big Bang, burn brightly in the blue end of the visible light spectrum.

Older galaxies, like our own Milky Way have had plenty of time to use up those primordial elements, mixing in heavier elements with generation after generation of supernovae.

Astronomers used to think that I Zwicky 18 was a rare example of a nearby, newly forming galaxy. Located only 59 million light-years from Earth, this galaxy could be used as a sort of time machine, to see the stages that galaxies went through early on in their evolution.

Well, the new observations from Hubble have dashed those hopes. I Zwicky 18 is old, possibly as old as the Milky Way, forming its first stars up to 10 billion years ago. With its sensitive instruments, Hubble was able to spot previously hidden red, older stars, showing that the galaxy has been forming stars for billions of years.

So how is it possible that such an old galaxy still has large quantities of primordial hydrogen and helium, but we see rapid star formation today? It’s possible that the galaxy has just been going slowly, forming stars at a dramatically reduced rate in the past. But something kicked that rate of star formation into high gear in the recent past.

Original Source: Hubble News Release

It’s time for another amazing image from Hubble. You’re looking at nebula NGC 3603, one of the most spectacular star forming regions in the Milky Way. It’s located about 20,000 light-years away from the Earth, in the Carina spiral arm. Apart from offering up pretty pictures, this region is important for science too. Birth and death, gas and dust, NGC 3603 has it all.

This Hubble image shows many different things happening, all at the same time. Most of the stars in the image were all born in the nebula, and differ in size, mass, temperature and colour. There are some absolute monsters in there, dozens of times the mass of our own Sun. These huge stars live fast and die young, burning through their hydrogen fuel quickly, and blowing out fearsome ultraviolet radiation. The combined radiation of all the stars has carved out an enormous cavity of gas and dust in the centre of the nebula – the clear region in the middle.

According to astronomers, the most massive stars are concentrated into the centre of the cluster. In fact, three of them seem to have more mass than is theoretically possible. Instead of single stars; however, they might be binary pairs, so close that even Hubble can’t distinguish them. The largest star was measured with a mass of 115 times the mass of our Sun. So, either the observations or the theories are wrong; stay tuned to see how this one plays out.

Around the swirling nebula are some darker regions called Bok globules. These are dark clouds of gas and dust with the mass of about 10-50 times our Sun. They’re under the process of collapsing, and will eventually form stars, but for now they’re some of the coldest objects in the Universe. You need cold gas before you can get hot stars.

The entire nebula seems contain about 400,000 times the mass of the Sun. That’s enough material for plenty of stars.

Original Source: ESA Hubble News Release

Planetary nebulae are some of the most beautiful objects in the Universe. Don’t let the name confuse you, though, they have nothing to do with planets. They’re all that’s left behind when stars at the end of their lives cast off their outer layers into space. Here’s a nice image released from the Hubble Space Telescope, containing 4 different planetary nebulae.

As a star like our Sun reaches the end of its long life, its ejects its outer layers in a series of dramatic events. The ultraviolet light from the star illuminates the material, causing it to glow like we see in this Hubble photograph. This same ultraviolet light also disperses the cloud of material, pushing it outward so that it eventually fades away into the vacuum of space.

Although the star might have lived for 10 billion years, its planetary nebula lasts for just a moment – only 10,000 years.

In this Hubble image there are 4 planetary nebula.

At the top left is He 2-47, nicknamed the “starfish” because of its shape. It has six different lobes, which indicates that the original star shed material three different times in three different directions. With each ejection event, the star blasted out twin jets of material.

At the top right is NGC 5315, which seems to have an x-shaped structure. As with the previous nebula, it suffered two different ejection events, casting away its outer layers and firing out jets in opposite directions.

IC 4593 is on the bottom left, and it’s in the northern constellation Hercules. My good friend Phil Plait actually did a cool write up about this object, so I link you to his site for the scoop.

And finally, NGC 5307 is down at the bottom right, and has a beautiful spiral pattern. The dying star might have had a serious wobble as it was expelling gas, creating the complex shapes in the picture.

Original Source: Hubble News Release

Let’s go back, way back, to an earlier time when the Universe was a fraction of its current age. Tiny galaxies, just a fraction of the mass of the Milky Way came together, piece by piece, building up larger and larger galaxies. Well, we don’t have a time machine, but we’ve got the next best things: Hubble and Spitzer, which were called upon to look back into the distant Universe, to watch this process unfold.

The new data gathered by the Hubble Space Telescope and the Spitzer Space Telescope reveal a collection of the smallest, faintest, most compact galaxies ever seen. These aren’t the majestic spiral galaxies we know and love, but primordial building block galaxies that played an important role in the evolution of the structure of the Universe. The two great observatories saw these galaxies when they were just a billion years after the Big Bang; in other words, the galaxies are more than 12 billion light years away.

The images from Hubble are key. It saw galaxies that only contained blue stars just a few million years old. These young, hot stars haven’t had a previous generation before them. They’re using the pure raw material of the Big Bang – mostly hydrogen and helium – as their fuel, unpolluted by heavier elements. Spitzer came in after and helped make accurate measurements of the galaxies’ masses.

“These are among the lowest mass galaxies ever directly observed in the early universe,” says Nor Pirzkal of the Space Telescope Science Institute and the European Space Agency in Baltimore, Md.

Three of the galaxies look distorted, with the familiar tadpole shape of a galaxy in a gravitational tangle with another galaxy. And this is how it started. These tiny galaxies merged with one another, growing into larger and larger objects, and eventually spirals like our own Milky Way.

The earliest time of the Universe is gradually coming into focus, thanks to these observatories.

Original Source: Hubble News Release

All right, this is the coolest thing ever. You know Google Earth, that cool software application that lets you explore satellite photography of the whole planet. Well, some clever Google engineers have flipped the software inside out, letting you explore the Universe with a similar interface.

This new addition to Google Earth is called “Sky in Google Earth”. It allows you to zoom around the heavens, with various Hubble Space Telescope images highlighted. You can click on the special objects, like the Orion Nebula, and then see the Hubble photograph of the region.

The images of the entire sky are made up from the Digitized Sky Survey and the Sloan Digital Sky Survey. The Digitized Sky Survey covers almost the entire sky, contains about a million objects. The Sloan Digital Sky Survey only has about 25% of the sky covered, but in much more detail, comprising hundreds of millions of images.

For all the images captured by Hubble, you can see bigger versions of the images, and then link out to press releases and additional resources on the web.

I’ve got to say, I’m really impressed with the way this project has started out. I can envision a future where more and more sky surveys are put into the program, and maybe even different observatories, so you can see what the sky looks like in X-rays, infrared, etc.

I think this will also help highlight how little of the sky has actually been captured in any detail. Perhaps this will spur on the development of additional robotic sky surveys to continue capturing the Universe in greater and greater detail. Still, it’s an amazing start – nice work Google.

To get a copy of Google Earth, go to http://earth.google.com/. The latest version of the software, 4.2, contains the additional sky watching features.

Original Source: Hubble News Release

Now this is one of the coolest images I’ve seen captured by the Hubble Space Telescope in a long time. It’s just a portion of the Veil Nebula; all that remains from a star that exploded about 5-10,000 years ago.

The star that created this wreckage was once much larger than our own Sun. Instead of dying out to a white dwarf – the fate for our Sun – it detonated as a supernova. The explosion swept out a huge bubble in its surroundings, heating up gas and dust, and becoming visible in our telescopes.

The Veil Nebula is huge. The entire shell covers about 3 degrees of the sky. That’s the same amount as 6 full moons. So these images captured by Hubble only reveal tiny portions of it. If you follow along to the original press release, you’ll see a series of 8 images in total, each focused on a different part of the nebula.

Scientists think that the original star exploded 5-10,000 years ago, and would have been seen by ancient civilizations. Anyone fortunate enough to be alive then would have seen light from the star increase until it was as bright as a crescent moon. But all this light would be streaming from a single point source. Amazing.

If you want to see the Veil Nebula for yourself, it’s located in the constellation of Cygnus, the Swan. The brightest star in the region is named 52 Cygni, and can be seen with the unaided eye on a dark night. You’ll need binoculars to see a hazy bit where the nebula is, and and a nice telescope to reveal more.

Original Source:ESA Hubble News Release