Found: Most Distant Galaxy Yet, Age 13 Billion Years

By Bill Andrews | October 23, 2013 12:00 pm
This Hubble Photo, full of galaxies, includes a zoomed-in view of the most distant known galaxy, z8_GND_5296, originating just 700 million years after the Big Bang. Credit: V. Tilvi (Texas A&M), S. Finkelstein (UT Austin), the CANDELS team, and HST/NASA

This Hubble Photo, full of galaxies, includes a zoomed-in view of the most distant known galaxy, z8_GND_5296.
Credit: V. Tilvi (Texas A&M), S. Finkelstein (UT Austin), the CANDELS team, and HST/NASA

There’s a reason “astronomical” also means a hugely large amount. Astronomers have found the most distant galaxy yet, one that dates back to just 700 million years after the Big Bang. That means its light traveled for more than 13 billion years, stretching along with an expanding universe, before finally arriving within the researchers’ instruments. Not only is that simply mind-blowingly cool, but the galaxy far, far away is also providing hints about what the early universe was like.

Going the Distance

The star city in question, which those in the know simply call z8_GND_5296, first turned up in a Hubble Space Telescope survey called CANDELS (Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey). The project — the telescope’s largest ever — discovered about 100,000 galaxies total, but ol’ z8_GND_5296 and 42 others stood out as potential long-distance record-breakers.

The astronomers took to the mountains to study these potential outliers: the Keck Observatory on Hawaii’s Mauna Kea volcano. Looking at the 43 galaxies in depth, only one had the kind of data they were looking for, a special kind of feature in its light spectrum called the Lyman alpha transition that indicated that it was exceptionally distant. The results appear in today’s Nature.

To be sure, there are other known galaxies that astronomers suspect might be even farther, but they haven’t been spectroscopically confirmed. Astronomers know where z8_GND_5296 is based on the way its light has been warped by the universe’s expansion, a phenomenon known as red shift because stretched light appears redder. Technically speaking, this galaxy has a redshift of z=7.51, which corresponds to a time 700 million years after the Big Bang — just 5 percent of the universe’s current 13.8 billion year age. Scientists estimate the galaxy now lies 30 billion light-years away from Earth.

Galaxy Goodness

Finds like this are important because they reveal what things were like in the young universe. In particular, z8_GND_5296 turns out to be unexpectedly rich in metals (which, to astronomers, means anything besides hydrogen and helium), as well as quite the star-forger, with a rate of about 330 solar masses per year (more than 100 times what our Milky Way forms). As the authors write:

Such a galaxy is unexpected in a survey of our size, suggesting that the early Universe may harbor a larger number of intense sites of star formation than expected.

Like most distance records, z8_GND_5296’s will probably not stand; better telescopes and imaging technology have always meant farther and older discoveries. But the insights it’s providing on conditions in the early universe and on galactic evolution will definitely stand the test of time.

CATEGORIZED UNDER: select, Space & Physics
MORE ABOUT: astronomy
  • Shelly

    beautifully majestic!

  • Marcus Brown

    If the universe is estimated to be 13.8 billion years old how can the galaxy be 30 billion light years away? Wouldn’t the light we’re seeing now have had to have traveled 30 billion years to get to us thereby exceeding the age of the universe?

    • Bill Andrews

      When the light left the galaxy, it was much closer to us. As the universe expanded during the light’s journey, so did the distance between Earth and ol’ z8_GND_5296. The light itself only traveled for about 13.1 billion years, but by now the galaxy is much further away. The light its emitting today would take about 30 billion years to reach us (if there were still an “us” here to reach) – course, by then, it would have grown even more distant!

      • alex

        but then the light will no longer reach us till 30 billion years again

    • Gregor McHardy

      Yes, I’m still waiting for an answer I can understand. I have asked this same question many times, and have yet to receive an answer that is both satisfactory and comprehensible. The closest I have come to understanding is someone telling me that “the fabric of space has expanded”, I guess meaning that the objects didn’t travel apart faster than the speed of light, but someone just built a few football fields between them when no one was looking. So please, someone give us an answer we can understand.

      Say something to us we can learn
      By heart and when alone repeat.
      Say something! And it says “I burn.”
      But say with what degree of heat.
      Talk Fahrenheit, talk Centigrade.
      Use language we can comprehend.
      Tell us what elements you blend.
      It gives us strangely little aid,
      But does tell something in the end.

      – Robert Frost

      • John Lavallee

        In the beginning everything that is and would ever be was created in less than a second and the material (all smaller than atoms) expanded faster than the speed of light (86,000 miles per second) because at that point it had no mass (weight or size that can be measured ). Once it took on mass it slowed but kept moving. That’s why it can be further away in light years because it started it’s journey faster than light speed( the distance light travels in 1 year (about 4,214,656,000,000 miles) is a light year, and no one really knows how far it spread before it took on mass. I hope it helps.

      • John Lavallee

        Sorry 186,000 miles per second would make it 5,849,625,600,000 miles in 1 year.

    • alex

      I agree with you if galaxies seem to be more than13.8 billion miles away thereby the age of the universe have to be resituated

    • alex

      You may have heard the term ‘light year’ used in science fiction or on educational channels about astronomy. But what exactly is a light year? The term light year refers to a measurement of distance, not time. It is the total distance traveled by light in one year. So when you hear the phrase ‘Galaxy X is 10 light years away’, then you can multiply the speed of light by 10 years to find out how far Galaxy X is from us. You can also think of a light year in terms of the time light takes to travel that distance. When we say Galaxy X is 10 light years away, that means that it will take light from Galaxy X ten years to reach the Earth.

  • colindenronden

    Just a teenager.

  • Hawkeye72

    At least once a month they announce “most distant galaxy yet is found”. Not only that but there was an actual Milky Way candy bar orbiting around it.


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