Using Hydrogen to View Truly Ancient Stars and GalaxiesCategory: Science & Technology
Posted: September 7, 2012 09:59AM
According to the Big Bang theory, the Universe is approximately 13.7 billion years old, and for a lot of that time, we have a good idea of what it looked like. Eventually galaxies formed that are similar to what we can view now, but at first the Universe was just occupied by a hot amorphous cloud of particles For the time in between, when the earliest galaxies and stars formed, we are not sure what everything looked like, but now researchers at Tel Aviv University have a way to find out.
Thanks to the photoelectric effect and quantum nature of electron orbitals, different materials emit different frequencies of light. This means specific molecules and atoms can be identified just by the spectra of the light they give off. The researchers have found that by looking at radio waves with 21 cm wavelengths that were emitted by hydrogen, they should be able to capture stars and galaxies from when the Universe was only 180 million years old (13.52 billion years ago). As the primordial galaxies and stars would have heated the hydrogen, by finding the areas of the sky with the most 21 cm photons, the researchers can map out where the star clusters and galaxies were at that ancient time.
Dubbed '21-centimeter cosmology' this new field of astronomy already has five international collaborations working to build radio telescopes explicitly for finding these emissions, but at the 500 million year old mark for the Universe. The researchers suspect what they find will be different from what current models predict for that time period.