Wednesday, March 3, 2010

Chandra X-Ray Observatory

This is the third, and last, post in my series of the NASA Great Observatories.
You can read my first post about Hubble here and my second post about Spitzer here.

Chandra X-Ray Observatory
This time I'll be talking about Chandra, which is observing the x-ray spectrum of light.

Artist impression of Chandra in space

X-rays are absorbed by the Earth's atmosphere so in order to get a really good look, we need to rise above it. The Chandra observatory does just that and gives us the ability to observe very hot regions of space such as the area around black holes, supernovae or areas with very high magnetic fields.

You will often see Chandra images in composites with images from other telescopes to better illustrate the measurements.

Remember: As always, you can click all images in this post to learn more about it.

Black Holes
At the centre of most (if not all) galaxies is a super massive black hole, feeding on the gas and matter surrounding it. The black hole at the centre of our galaxy (The Milky Way) is called Sagittarius A*.
It was believed to be feeding very little on the surrounding matter and Chandra was pointed towards it for almost 1 million seconds (around 2 weeks) to figure out why.
And apparently it was feeding a lot less than expected, perhaps due to the gas being blown away from the black hole due to energy transfer between the hot inner regions and the cooler outer regions.

Sagittarius A*

The next image shows a remarkable eclipse captured by Chandra. The eclipse is caused by a large dense could of gas moving in front of the black hole at the centre of the galaxy.
In the small inset, the black hole is the very bright dot near the centre of the image.

Eclipse of a black hole

Chandra looked at the supernova remnant G1.9+0.3, which was previously spotted by the Very Large Array in 1985. The supernova is very young and Chandra discovered that it is around 140 years old. The image below shows Chandra data (from 2007) in orange and the 1985 data in blue.
This is the most recent supernova in our galaxy.

 Remnant of recent supernova

The crab nebula is extremely cool. It's the remnants of a supernova seen by astronomers in 1054 and it's absolutely amazing (you can see Hubble's view of the nebula here).
Chandra showed us something equally amazing, how the x-ray emitting pulsar at the centre of the nebula lights up the entire nebula with spray of matter and anti-matter (a pulsar is a rapidly rotating, highly magnetized neutron star).
An indescribably cool image.

 The Crab nebula in x-rays

The final supernova image shows the difference between two types of supernovae. On the left is the Type Ia and on the right is a Type II.
Type Ia is when a white dwarf star accretes mass from a neighbouring star until it reaches critical mass and the outer layers explodes in a massive explosions.
Type II is a "core-collapse" supernova, which occurs when massive stars have shed their outer layers and the core becomes too massive and an implosion occurs, leaving behind a neutron star.

Two types of supernovae

More images
I've only scratched the surface here, Chandra has produced a lot of fantastic images.
You can see a lot more cool Chandra images at the official Chandra Flickr page.
Or at the official Chandra site.

That concludes my tour of the Great Observatories.
There are still plenty of space telescopes to talk about (Kepler, SOHO, Planck, STEREO, etc) or amazing probes (LCROSS, Cassini, etc), so you will see many more posts like this, featuring cool and educating images of our universe.