Science

NASA’s galaxy quest: oldest known galaxies detected

NASA may have discovered the most distant galaxy known to human knowledge. Initial reports suggest that this small galaxy, known as Abell2744_Y1, could be about 13.2 billion years old. In comparison, our universe is believed to be 13.8 billion years old.

Abell2744_Y1, is approximately 30 times smaller than the Milky Way, but produces up to 10 times more stars than our own. This is a normal amount for smaller galaxies such as this one. The galaxy was discovered by NASA’s frontier field programme using a combination of the Spitzer and Hubble telescopes to capture images.

It also utilised the Chandra X-ray observatory, a telescope that is specially designed to detect X-ray emissions from very hot regions of the Universe, such as exploded stars, clusters of galaxies and matter concentric to black holes.

The Hubble, although the flagship of NASA, is limited in that it can only catch shorter wavelength infrared light, whilst the newer and more advance Spitzer uses the full spectrum of infrared light in order to capture images.

The frontier field’s programme will collect pictures of six galaxy clusters in total. Hubble takes the rudimentary images of the galaxies to be investigated from great distance, while the Spitzer takes over to determine whether the galaxies are as far away as they seem. In the past, this combination has created beautiful gossamer images of galaxies.

Abel2744 Y1 has a redshift of 8. Redshift is a variation of the Doppler effect, occurring when light or other electromagnetic radiation from an object moving away from the observer is increasing in wavelength, or shifted to the red end of the spectrum.  The red comes from the increase in wavelength, equivalent to a lower frequency and photon energy. Because the universe was created in a big bang, objects are moving away from the epicentre; therefore, the greater the rate at which the distance between galaxies increases corresponds to a larger redshift. The furthest confirmed galaxy to date had a redshift of 7, while other candidates have been identified with a redshift of 11, but are yet to be confirmed.

“Just a handful of galaxies at these great distances are known,” said Jason Surace of NASA’s Spitzer Science Centre in Pasadena. “The Frontier Fields program is already working to find more of these distant, faint galaxies. This is a preview of what’s to come.”

With the James Webb Space Telescope’s launch on the horizon, Hubble’s successor, we truly are on the precipice of discovering evidence of life beyond our galaxy and answering salient questions about the Universe.

Thomas Bamford

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