Are you ready to have your mind blown by the awesomeness of science, and the grandeur of the universe?
If so, read on.
Let’s begin in 2009, when space shuttle Atlantis flew to the Hubble Space Telescope and added several improvements, including the wide field camera 3. This camera added the capability for the telescope to see into the near-infrared portion of the spectrum — light with a slightly longer wavelength than that of visible light. This light, it turns out, is very good for studying distant galaxies.
Using this new Hubble camera in 2012 a large team of astronomers identified a number of interesting objects they wanted to study further with ground-based telescopes, which although they do not have the benefit of being located above Earth’s blurring atmosphere, do have larger mirrors.
On two nights in April some University of Texas and Texas A&M astronomers got time on one of the two largest telescopes in the world, the Kecks, in Hawaii.
They patiently took data on about 40 objects that the Hubble data indicated might be galaxies that formed in the early universe. To the surprise of the astronomers, only one of them was a hit.
“We were excited and disappointed at the same time,” said Steve Finkelstein, an astronomer at the University of Texas who made the observations.
But oh, what a hit. It turns out that the object — catchily named z8_GND_5296 — was a galaxy nearly 30 billion light years from Earth. What they were seeing is the galaxy as it existed about 700 million years after the Big Bang. A paper describing the discovery is published today in Nature (see abstract).
For a universe that 13.8 billion years old, that’s the baby years. In fact, astronomers have never observed a galaxy that’s older than this. Finding objects this old, when galaxies and stars were only first beginning to form, is essential if scientists are to piece together the story of how our universe developed.
What’s surprising is that only one of the 40 objects on their list turned out to be a distant galaxy. Where were the others?
The answer may have to do with a cosmic fog — pervasive hydrogen gas that existed throughout the universe during the first 500 million to 700 million years of the universe’s existence. This neutral hydrogen effectively shrouds most early galaxies from existing telescopes.
So what burned off this cosmic fog? It was actually the first really big and bright stars — about 20 to 100 times the size of our sun. These stars emitted very energetic light particles that collided with the electrons zipping around hydrogen atoms. When these photons have enough energy, as those do from very bright stars, they strip off the electrons.
The time when this process occurred is called reionization, and the discovery of this galaxy is helping astronomers to understand when and how it occurred. The universe we live in today remains ionized. Here’s a graphic that shows when and how some of these processes occurred.
What’s with the Aggies and Longhorns working together, anyway? Turns out astronomers from the two departments work closely with one another, and are collaborating with other institutions to build the Giant Magellan Telescope. When it opens, as early as 2018, this will be the largest telescope in the world — 2.5 times the size of the Kecks.
And it will allow Texans to see even further back into the early days of the universe. If everything’s bigger and better in Texas, astronomy ought to be no exception.