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Astronomers Spot Most Distant Galaxy—At Least For Now

“A long time ago in a galaxy far, far away” doesn’t even begin to describe a small, bright galaxy hovering at the edge of the observable universe. The little cluster of stars, called GN-z11, is the most distant object astronomers have spotted: It existed when the universe was just 400 million years old.

“This is a very early galaxy,” says UC-Santa Cruz’s Garth Illingworth, who described the galaxy in The Astrophysical Journal. “We’re looking back 13.4 billion years, through 97 percent of all time, to the galaxy when it was forming.”

Yep, it took 13.4 billion years for light from the galaxy to zoom through the universe and collide with the Hubble Space Telescope. But that doesn’t mean the galaxy is 13.4 billion light-years away. The universe has been expanding in the meantime, meaning GN-z11 is actually much, much farther from Earth than that.

“Right now, we expect this galaxy to be about 32 billion light-years away from us in distance,” says study coauthor Pascal Oesch of Yale University.

In other words, the galaxy existed a ridiculously long time ago and is really, really, absurdly far away. To put it politely.

A Precocious Star Factory

When you peer into the distant universe, you’re also looking back in time. So the galaxy in its present form would look very different than what Hubble sees now.

The newest most-distant galaxy found existed when the universe was just 400 million years old. It's located on the sky near the constellation Ursa Major, but is super duper far away. (NASA/ESA/P.Oesch)
The newest most-distant galaxy found existed when the universe was just 400 million years old. It’s located on the sky near the constellation Ursa Major, but is super duper far away. (NASA/ESA/P.Oesch)

But 13.4 billion years ago, this bright little knot of a billion stars was about 1 percent the size of the Milky Way. Despite its size, the precocious galaxy was pumping out stars much more quickly than the Milky Way. Those stars were very hot, very young, and very massive—the types of stars astronomers think existed in the early universe.

They just didn’t expect to see them so soon.

“We really did not expect to find a galaxy this bright, this early, in the history of universe,” Oesch says. “The big question is, how common are galaxies this bright so early in cosmic history? I don’t think there’s too many out there. I think we were lucky.”

Not For Long

History has taught us that astronomical distance records don’t hold up for long. The previous most-distant galaxy, called EGSY8p7, was reported in July 2015. It’s about 200 million or 300 million years younger than GN-z11, and has a redshift of 8.68. (Redshifts measure how much light has stretched as it travels through the cosmos; higher redshift values correspond to greater distances.) Before that? The winner was EGS-zs8-1, a galaxy that’s another 200 million years younger, and was reported in February 2015. It has a redshift of 7.78.

The new record-holder is at redshift 11, which is a number I hadn’t really expected to see at this point. For what it’s worth, light from the cosmic microwave background—a remnant of the Big Bang—has a redshift of 1,089.

Each newer, sharper eye in the sky reveals ever more distant and intriguing objects. So even though GN-z11 is the winner for now, it’s likely to hold onto its title for less time than an Olympic gold medalist. In 2018, the James Webb Space Telescope will launch, and if everything goes well, its ability to peer back in time will be even more impressive than Hubble’s.

“We’re basically at the limit of Hubble,” Illingworth says. “If you go out a little bit further, there is no light. Hubble can’t see anything.”

17 thoughts on “Astronomers Spot Most Distant Galaxy—At Least For Now

  1. I’m fairly new to this site and know nothing about astronomy. Please can someone briefly explain to me what this means “When you peer into the distant universe, you’re also looking back in time. So the galaxy in its present form would look very different than what Hubble sees now”. I just don’t get it

    1. @Fort. When in astronomy they look at objects at far distance they tie in time with it. It goes back to physics.

      For example. If I stood a mile from you and was giving off light, you would see my light come to you 1mile divide by speed of light = some microsecond. However, think about this. You’re seeing my light that much time before because the light had to cover a mile distance to get to you.

      Same thing about Sun. Light from Sun takes 8.3 minutes to get here since Sun is 93 million miles away. So you’re looking at Sun when it was 8.3 minutes ago because you’re not there. If the Sun were to disappear Right now, you’ll still see light for 8.3 minutes and then completely darkness. So Time is tie to Space distance.

      Hence Space/Time are one when they talk in Physics. Nothing is instant even if you’re 1 millionth fo a meter away from that object, because light has to travel that much distance and time has past during that distance.

      I hope that explains it. So they’re seeing light from this Galaxy 13.2 billion years ago because light took that much time to travel to get here. If you were there, the distance would be different and galaxy would be different. If you want to look at the galaxy in “Now” moment, you’ll have to wait 13.2 billion years from now to say.. oh that’s how that galaxy looked in “my 2016 time”.

      1. Thanks Rink. It makes sense now. Since I don’t know much about science and astronomy, that paragraph seemed first like something out of a sci-fi movie.

        1. That’s the beautiful thing about science…the only limits are our imagination and capacity to understand.

    2. >>>>>So the galaxy in its present form would look very different than what Hubble sees now”. I just don’t get it<<<<<<

      As mentioned, it takes time for the light emitted at one point in time by a star to cross space and get to earth so it can be seen. Here when looking at a nearby light, light transmission seems instantaneous, but it isn't. They estimate that the discussed galaxy is now ~32 billion light years distant from earth. To see the light emitted today by that galaxy, if it still exists, would take 32 billion years, so 32 billion years from now, that light from today will pass this way.

      The "if it still exists" is a problem, because it may not.

      It is very possible that galaxy does not exist today; it may have been destroyed in a collision with another galaxy or ceased to exist due to a variety of dangers, but if there is light exiting that galaxy today, earth and our solar system along with our galaxy may not be here any longer when that light transits space and reaches this point 32 billion years from now. In astronomy, tremendous distances and times are the norm. Stars and galaxies, although eternal to us, are not eternal in actual time. They also live and die.

      I calculated the distance of 13.4 billion light years yesterday :

      (a light year: the distance light will travel in one year at the speed of light, 186,282 miles per second)

      13,400,000,000 X 365 X 24 X 60 X 60 X 186,282 miles per second or 299,792 kilometers per second = 7.87194946E22 miles from earth.

      Today's estimated distance:

      32 billion light years = 32,000,000,000 × 365 × 24 × 60 × 60 × 186282 = 1.87986853E23

      Couldn't resist! If we're vacationing there, we need to change our plans! 🙂

    1. @MeasureHow: Astronomers have many different tricks for measuring the distance to various astronomical objects. For objects that are as far away as this galaxy, I think they go (exclusively?) on the redshift, which is a measure of how much space has stretched while the light has been in transit (and hence is a measure of the distance, as we know the speed of light). Basically as the photons are stretched, their wavelength is increased, and they are therefore shifted towards the red end of the spectrum (blue light has shorter wavelength, red light longer).

      For a nearby object to have a redshift of 11, it would need to be moving away from us at 99.7% the speed of light, which is inconceivable.

  2. IMHO it is not the most remote galaxy discovered. Campagne 2012 HUDF show z=11.9.
    EGSY8p7 is not the 2d farest, it is MACS0647-JD discovered in 2013 with z=10.8

  3. Something that has perplexed me since my youth and I am now 80 years young and when I would ask folks all I would get is a blank stare.

    If the universe is constantly expanding, what is it expanding into?

    1. That’s a good question without a good answer, to my knowledge. We don’t “know” what is out there, other than a guess. There may be many universes side by side, or we could be in a Mason Jar on a shelf in God’s science lab.

      My guess is infinite space, whatever and wherever that may be. I suspect, but we may never know, that whatever we exist in (space) goes on and on, with even more universes outside our own.

      You asked a good question that I think has been a question for humans as long a we have had the ability to perceive and think, but that question will go unanswered possibly forever.

  4. If the Big Bang Theory is really correct, then Galaxies have been flying apart from that central point in all directions since it happened. Have scientists ever calculated where the actual center of the universe is located, not when, but where the actual Bang occurred? A second question: What caused the Big Bang? Have scientists ruled out “a creator”. I find that what I see out there and here on earth too beautiful to just be an accident. Chaos theory doesn’t compute with what I see.

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