Cosmic Quiz Question – The Farthest Galaxy?

Seth Jarvis

This week’s winner of the Clark Planetarium, KUTV-2 Cosmic Quiz is Zachary Griffin. He wants to know, “What is the farthest known galaxy?”

There are several galaxies that are good candidates for the farthest-known galaxy, but what they all have in common is they’re roughly 13 billion light years distant. That means that when astronomers see these galaxies they’re seeing light that has been traveling for about 13 billion years.

It’s amazing to see something that far away because the universe itself is only 13.7 billion years old. We’re seeing the way this galaxy looked less than a billion years after the universe began. These photons of light have been in transit for 95% of the age of the universe.

A quick note about galaxies: We live in a galaxy called the Milky Way. It’s a giant, slowly spiraling collection of about 200 billion stars and it measures about 100,000 light years in diameter.

Our Sun is an ordinary star located about 30,000 light years from our galaxy’s center.

mw-galaxy_450

Our Milky Way Galaxy

Our nearest galactic neighbor is the Andromeda Galaxy. It’s slightly larger than the Milky Way Galaxy and is located 2.5 million light-years from us. It’s a favorite target for amateur astronomers and is the most distant object visible to the unaided eye. You’ll notice a lot of stars surrounding the Andromeda Galaxy in the image below. Those stars are the stars of our Milky Way Galaxy in the foreground, only a few hundred or thousand light years distant.

andromeda-galaxy2_450

Andromeda Galaxy - Galactic Neighbor

Not all galaxies are beautiful spirals, but the Milky Way and Andromeda Galaxies are.

To appreciate how far away the most distant observed galaxy is, it will help to make a scale model.

If you shrunk the Milky Way Galaxy down to about the size of a salad plate (about 7 inches), then the Andromeda Galaxy becomes the size of a dinner plate roughly 12 feet away.

Scale Model: Milky Way Galaxy to the Andromeda Galaxy

Scale Model: Milky Way Galaxy to the Andromeda Galaxy

2.5 million light years shrunk down to 12 feet. Intergalactic distances within a small room. Wow, that’s quite a cosmic crunch.

Now that you’ve got that kind of scale in mind, you can begin to appreciate just how far away the “farthest” galaxies are.

At the scale we’ve just created, the farthest galaxies are twelve miles away. That’s the distance from downtown Salt Lake City to Sandy.

Downtown SLC to Sandy - 12 Miles - Scale Distance to Farthest Galaxies

Downtown SLC to Sandy - 12 Miles - Scale Distance to Farthest Galaxies

And what’s in between?

To answer that question – try thinking about this:

Imagine you’re looking at a region of space as empty as any you’ve been able to detect. You’ve chosen a tiny black bit of the night sky near the Big Dipper that’s only the size of a grain of sand held at arm’s length.

Now imagine that you’ve got the Hubble Space Telescope available to you, and you ask it to stare at that tiny speck of empty space for about ten days, non-stop.

What does the Hubble Telescope see in that “empty” bit of space the size of a grain of sand at arm’s length?

This:

Hubble Space Telescope Deep Field: An image of "empty" space

Hubble Space Telescope Deep Field: An image of "empty" space

Everything you see in this image is a galaxy, each containing billions of stars. Some of these galaxies are only a few hundred million light-years distant. Some are billions of light-years from us.

One more time, that’s an image of a piece of “empty” sky the size of a grain of sand held at arm’s length. It turns out that deep space looks like this in all directions. Galaxies everywhere. The current estimate is that there are something on the order of 100 billion galaxies in the universe.

So, does it really matter how far away the farthest galaxy is?

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18 thoughts on “Cosmic Quiz Question – The Farthest Galaxy?

  1. Hi……if i could meet Jehovah,i would ask him,”now whats the point of creating all this and why are they running from each other ,and to where???..and what next??

  2. Wow… I would say in a few million years from now we’d probably be checking out what’s out there in those specks of light – each an enormous galaxy like our own. The Universe is truly big and that is just the observable part.

  3. According to the Big Bang theory a galaxy at a distance of 13 billion Light Years must have travelled away from us with an average speed of more than 18.5 times the speed of light, which are the forces accelerating the galaxy to maybe 36 times the speed of light, then decelerating to just below the speed of light and then keeping that speed constant. If the receding speed of that far away galaxy would be higher than the speed of light, it would not be visible to us. If the deceleration would continue we would see some far away galaxies with very little Red Shift, which is not the case. These far away galaxies are not easily explainable with the Big Bang theory!

  4. I think there is planet that we could live out there in a galaxy. I think we are so miles away from there. I don’t know what will happen to our Earth because we are using lots of resources and the earth soil.

  5. All these pictures are fake, but who cares, you all believe it. And No, it serenely does not make any sense. Perhaps you can explain how was the picture of our galaxy made?

  6. Michal,

    The only “fake” picture in the post is the artist’s rendering of the Milky Way Galaxy.

    I’ll take the blame for not labeling that image as artwork. I guess I took it for granted that if I posted an image and labeled it “The Milky Way Galaxy” that folks would know that an actual image of our galaxy from that perspective had to be a simulation.

    We know a lot about the size and shape of the Milky Way galaxy from careful studies from our location within it. We know our distance from the galaxy’s center and our location on one of our galaxy’s spiral arms by studying the location and spectra of other stars within our galaxy and the distribution of hundreds of Globular Star Clusters that orbit our galaxy.

    The last image in the post, the famous “Hubble Deep Field” image of thousands of galaxies, represents one of the most significant images captured by Hubble. The universe is genuinely an amazing place – no fakery is required to represent just how amazing it is.

    “Faking” a Hubble image is a virtual impossibility. There are far too many researchers minutely examining Hubble data and double-checking Hubble data against data from other telescopes to ever permit a fraudulent image to be represented by NASA/ESA as a real Hubble image.

  7. A question for you Seth Jarvis, did you read my comments on 12 August 2010, don’t you think this comment deserves an answer, or do you find it perfectly logical that a far away galaxy accelerates to 36 times the speed of light, then decelerates to just under the speed of light and then stays at constant speed, all in the time of only 700 million years?
    Please advise and regards,
    Taco Smit

  8. Taco,

    A common misconception is that the expansion of the universe consists of galaxies flying away from each other through space. In reality, the distance between galaxies increases as the space between them stretches and expands. As light travels through this expanding space, it is stretched by the same factor as the universe, causing its wavelength to increase. As blue light has short wavelengths and red light has long wavelengths, this stretching shifts the light towards the red and it is called a redshift. Redshift in this case (sometimes called the cosmological redshift) is a measure of how much the universe has expanded since the time the light was emitted, not a direct measure of velocity. As an example, all that can be stated correctly about an object with a redshift of 2 is that the universe expanded 200 percent between the time the object emitted the light and the time it was received. Far away galaxies have higher redshifts because the universe has expanded more during the additional time it has taken light from those galaxies to reach us.

    Complications arise in calculating particular distances and recession velocities of galaxies from cosmological redshift measurements as General Relativity is needed to correctly describe an expanding universe.

    However, even without using General Relativity to do the calculations, a recession velocity greater than the speed of light is not needed for a galaxy to be at a distance of 13 billion light years in a universe that has been expanding for more than 13 billion years.

  9. Robert, I am sorry but I cannot agree with you. If we see a galaxy at 13 billion light years, we do not see that galaxy now but a galaxy which was at 13 billion light years away 13 billion years ago.
    If as the Big Bang theory says the universe is 13.7 billion years old that means that a galaxy must have moved away from us 13 billion light years in maximum 700 million years. Distance divided by time gives the average speed the galaxy receded from us and this gives an average speed of a bit more than 18.5 times the speed of light, because that galaxy was already 13 billion light years away when the universe was only 700 million years old. The only way out is that the red shift has another origin than to be a doppler effect of receding galaxies. By the way Hubble did not believe that the galaxies were receding and spoke only of an apparent receding speed, but thought the red shift must have an other explanation!

  10. The distance to a remote galaxy is calculated from the (measured) redshift of light from the galaxy. Since this redshift is a measure of how much the universe has expanded since the time the light was emitted, the distance that results from these calculations is NOT the distance of the galaxy when the light was emitted. It includes the increase in distance that results from the expansion of the universe. A galaxy at a calculated distance of 13 billion light years was MUCH closer when the light was emitted. As I tried to explain in my previous post, the cosmological redshift is not a manifestation of the “doppler effect of receding galaxies”. It results from the expansion of space between galaxies.

    Incidentally, calculating average velocity using “distance divided by time” is a non-relativistic approximation. It only yields accurate results for speeds that are much lower than the speed of light. For speeds close to the speed of light it gives wildly inaccurate results.

  11. If the measured red shift is taken as an accurate way to calculate the distance of that galaxy and the measurement gives a distance of 13 billion light years the controversy stays valid, how could that galaxy reach that distance from us in only 700 million years, according to the relativity theory nothing can go faster than the speed of light and you cannot deny that the light from that far away galaxy took 13 billion years to reach us. There are more problems with the Big Bang theory, it is hardly acceptable to start with a singularity and to claim that all our theories about conservation of mass and energy are at once not valid anymore. The inflation phase in the BB theory is an incredible theory inside another incredible theory, I think it would be time to look for alternative theories, which don’t deny common sense.

  12. A galaxy at a calculated distance of 13 billion light years took about 13 billion years to reach that distance, not 700 million years.

    Contrary to what has been written by some, conservation of mass/energy is still valid within the framework of the Big Bang model. This is one example of many inaccurate statements about Big Bang cosmology that I have read (mostly on the internet). A clarification here may be helpful.

    The Big Bang theory results from a scientific model that uses General Relativity to describe the universe. This model is used to make predictions about the universe that can be tested by comparing these predictions with observations. The model is incomplete. Among other things, it does not describe conditions at the very earliest time (less than 10^-43 seconds) which would require a quantum theory of gravity. There have been many ideas put forth about what might have occurred during this early period including what caused the expansion. However, these ideas are speculation and are not really part of the Big Bang model.

    There is a NASA website that has a good summary of Big Bang cosmology which also addresses some common misconceptions.

  13. Let me see if I can explain part of this another way:

    The galaxy wasn’t 13 billion light years away when the light was emitted. It was substantially closer. Between our own galaxy moving away from it and the universe itself expanding, it has now reached a point where the light took 13 billion years to reach us.

    Imagine two moving sidewalks, parallel and next to each other (something you might find in an airport). Near the middle of each one, you have a person standing with some luggage, a few feet away from each other. The sidewalks begin to move in opposite directions. Person A begins walking slowly in the direction that their sidewalk is moving. Person B begins walking faster against the flow of their sidewalk, trying to catch up to Person A. Person A represents our galaxy receding from the other. Person B is the light from that other galaxy moving towards our own. And the moving sidewalks represent the expansion of the universe. Even though Person B is walking fast, it will take him quite some time to catch up to Person A, due to the combined effects of both sidewalks and Person A’s own motion. So, despite Person A and B starting very close to each other, it takes Person B a long time to reach Person A. And if Person A were then to look back to Person B’s luggage, he would find that it was quite a distance away by that point.

    Hopefully, this analogy makes sense.

  14. If you believe the BB theory and that the universe has an age of 13.7 billion years the light of galaxies at distances of 7 billion light years or more could not yet have reached us and should be invisible to us.
    The fact that we do see these galaxies means that the universe is static and not expanding.
    The red shift may very well be an effect of ether flow, which causes gravity for matter and also anti gravity for anti-matter, the gravity attraction should be in balance with anti-gravity repulsion and matter and anti-matter should exist in equal quantities, so all natural forces are in balance and the universe may be much older than 13.7 billion years, which gives a much better explanation for the galaxy clusters and bands, which could never form in an expanding universe.

  15. Robert Bigelow, let me answer you on your first sentence of your February 16 comment. You said: A galaxy at a calculated distance of 13 billion light years took about 13 billion years to reach that distance, not 700 million years.
    If that would be true, you have to agree that the light of that galaxy, at that distance, takes 13 billion years to reach us, so the total age of that galaxy must be 26 billion years according to your calculation, which is in conflict with the BB universe age of 13.7 billion years!

  16. Taco, the 13.7 billion year age of the universe has been established through careful observation of numerous distant supervova of known brightness. The antiquity of the universe is further corroborated by the cosmic microwave background radiation.

    I think where you’re confused is in the expansion of the universe. There’s no round-trip travel time involved – space itself has expanded to carry the universe’s earliest galaxies to extreme distances. Light from the most distant galaxies has red-shifted due to the expansion of space itself between us and those galaxies.

    Moreover, there’s absolutely no observational evidence of “ether flow” or of a static, non-expanding universe.

  17. Seth,
    You must admit that if space expanded to bring a galaxy at the distance of 13 billion Light Years and the light of that galaxy has traveled 13 billion years to reach us, with the age of the universe of 13.7 billion years, we see now a galaxy which cannot be older than 700 million years. My question is, how can we see that galaxy when the average expansion speed of the space between us and that galaxy was more than 18,5 times the speed of light.

    Has the expansion suddenly stopped or at least so much slowed down that after 700 million years the expansion speed is lower than the speed of light, otherwise the light could not have reached us yet?

    For the observational evidence of ether flow the following example: If we are in deep space and accelerate our space ship or satellite, it will cause an inertia force which has the exact same character as a gravity force. This happened because we accelerate in the ether.

    So if you do not accelerate on the surface of the Earth, is it not logical and obvious to conclude that the gravity force is caused by an ether flow into the Earth! So it seems that matter absorbs ether and anti-matter therefore should emit ether, also for this there is some proof, the mysterious drift towards the Sun of Pioneer 10 could be explained by an ether push caused by anti-matter, which is evenly distributed throughout the universe and causes also the redshift in a static universe. I know that the BB Theory is in fashion at present, but there are many reasons to keep an open mind for other solutions.

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