Scientists Discover Farthest, Oldest Galaxy

SCIENCE

A team of researchers has identified the oldest, most distant galaxy yet discovered. (Tech Times)

Use our resources to swing by some of the other galaxies in our universe.

Teachers, scroll down for a short list of key resources in our Teachers’ Toolkit.

Galaxy EGS8p7 is the oldest, most distant object yet identified in the universe. Above, EGS8p7 is seen from the Hubble Space Telescope (wide and top right) and Spitzer Space Telescope (inset, bottom right). Photographs by I. Labbé (Leiden University), NASA/ESA/JPL-Caltech

Galaxy EGS8p7 is the oldest, most distant object yet identified in the universe. Above, EGS8p7 is seen from the Hubble Space Telescope (wide and top right) and Spitzer Space Telescope (inset, bottom right).
Photographs by I. Labbé (Leiden University), NASA/ESA/JPL-Caltech

Discussion Ideas

  • EGS8p7 has been identified, at about 13.2 billion years old, as the oldest and most distant galaxy yet detected. What is a galaxy?

 

The electromagnetic (EM) spectrum ranges from low-frequency “red” radio waves to high-frequency “blue” gamma rays. A tiny sliver of the EM spectrum is visible light. Illustration courtesy NASA

The electromagnetic (EM) spectrum ranges from low-frequency “red” radio waves to high-frequency “blue” gamma rays. A tiny sliver of the EM spectrum is visible light.
Illustration courtesy NASA

 

  • Why are light and redshifts from the oldest, most distant galaxies difficult to detect?
    • The early universe was a hot, cloudy, soup—not very good at transmitting light.
    • “Right after the Big Bang, the universe was basically a big mess of charged particles. Photons were scattered by free electrons and thus the early universe could not transmit light. Within 380,000 years after the Big Bang, the universe had cooled down enough for the free electrons and protons to combine,” creating crystal-clear neutral hydrogen. This period is nicknamed the Epoch of Reionization.
The Epoch of Reionization is represented by the lavender shading here. To the far right is Hawaii’s W. M. Keck telescope, used for observation of EGS8p7. To the far left is the Big Bang. EGS8p7 is at the center. The top scale indicates the progression of ever-more-distant discoveries and the corresponding year. The bottom scale is a time scale equivalent to distance. Finally, the inset at the top left charts the observations of EGS8p7 made across two nights with the Keck’s multi-object spectrometer for infrared exploration (MOSFIRE). Image by Adi Zitrin/ Caltech

To the far right is Hawaii’s W. M. Keck telescope, used for observation of EGS8p7. To the far left is the Big Bang. The Epoch of Reionization begins with “recombination.” EGS8p7 is at the center. The top scale indicates the progression of ever-more-distant discoveries and the corresponding year. The bottom scale is a time scale equivalent to distance. Finally, the inset at the top left charts the observations of EGS8p7 made across two nights with the Keck’s multi-object spectrometer for infrared exploration (MOSFIRE).
Image by Adi Zitrin/ Caltech

 

TEACHERS’ TOOLKIT

Tech Times: Caltech Scientists Discover Farthest And Oldest Galaxy: Say Hello To EGS8p7

Nat Geo: Hubble Captures Colorful Universe

Caltech: Farthest Galaxy Detected

(extra credit) The Astrophysical Journal: Ly? Emission from a Luminous z=8.68 Galaxy: Implications for Galaxies as Tracers of Cosmic Reionization

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