In the last post (It’s Full of Galaxies) we saw an infrared image from the Herschel space telescope looking at a tiny piece of the cosmos revealing thousands of galaxies 10 – 12 billion light-years from us. The image below is also an infrared image, but it is a view of millions of galaxies as taken by the 2MASS (Two Micron All Sky Survey) looking across the night sky.
The blue band in the image comes from the stars in our own galaxy. Note that the distribution of galaxies is not uniform, as one might expect but there are clusters, strings and webs of galaxies. These structures are remnants of the big bang and the gravitational attraction between matter and the mysterious dark matter. Think about this: All of the matter we can see and account for in the Universe only adds up to about 4-5% of the total mass of the Universe!
The 2MASS survey was conducted using two 1.3 meter telescopes, one in Arizona and the other in Chile, imaging the sky at 3 separate frequencies in the near infrared. Imagine what this would look like if we were able to use telescopes in space that are above the filtering effects of our atmosphere in the infrared.
Check these links for more information and a larger image.
Till next time,
These are not stars but galaxies, thousands and thousands of them and each one containing billions of stars. This snapshot from the Herschel infrared space telescope shows galaxies that are 10-12 billion years old with the red ones being the most distant. The white ones indicate galaxies with the greatest star formation. Looking closely at the image one does not see an even distribution of dots/galaxies, which indicates that some of these galaxies were forming in clusters at that time.
This image was one taken as part of the Herschel Multi-tiered Extragalactic Survey (HerMES) Key Project. The purpose of the project is to study the evolution of galaxies in the distant cosmos. This particular image lies in a region of space called the Lockman Hole, which is in the constellation of Ursa Major and provides a relatively unobstructed view into a far corner of the Universe.
The next night you are out, take a look up into the night sky and think about the fact that all you can see is in the optical region of the spectrum. Consider what lies beyond our narrow view of the vast cosmos.
Till next time,
It is way too easy to dismiss the Universe as a static entity that doesn’t change as we go about our daily activities. We catch a glimpse of the night sky from time to time, but never stop and watch it night after night as our ancestors did. Thanks to modern technology we can compress years into seconds, and see amazing things unfold that we would have missed otherwise.
A good example of this is the supernova 1987A (which occurred in 1987) in the Large Magellanic Cloud. In this video you can see how the shock wave has propagated through space from 1994 to 2006. This image from Hubble (below) shows in even better detail the shock wave as it heats the gas and dust that were ejected from the star thousands of years before it went nova.
Another video that always amazes me is one from the European Southern Observatory (ESO) that shows the stars at the center of the Milky Way orbiting around a dark common point over a period of16 years. This common point is undoubtedly a massive black hole. It can not be seen in the images, but by the motion of the stars, the mass of the object has been calculated to be about 4 million times the mass of our Sun. You can read more about this in an article I did: “Stellar Motion: Do Stars Really Move?”
Our Universe is constantly changing. We just have to slow down enough to see it.
Till next time,