Hubblecast Video Explains How Hubble “Looks Back in Time”

This seven-minute Hubblecast video helps explain how Hubble “looks back in time” to see the Universe as it was billions of years ago.

Hubblecast 68: The Hubble time machine

For episode 68 of the Hubblecast, Hubble transforms into more than just a telescope — it becomes a time machine! How can Hubble “look back in time” to see the Universe as it was billions of years ago? Dr. J explores the vast scale of our Universe, explaining how Hubble can be used to grasp cosmic distances, view very distant galaxies, and even explore our own past.

This video shows part of the IMAX short film “Hubble: Galaxies Across Space and Time”. This film transforms images and data from the NASA/ESA Hubble Space Telescope into a voyage that sweeps viewers across the Universe and back into cosmic history. The film pans through the vibrant and diverse panorama of thousands of galaxies in an image from the Great Observatories Origins Deep Survey (GOODS). The ensuing 3D journey through these galaxies provides more than just a new perspective in space; it also takes the audience back in time. Because light takes time to journey across space, the galaxies farther away from Earth are seen further back in cosmic history. The virtual voyage reveals galaxies as they appeared billions of years ago, when they were still in the process of forming.

This clip takes an illustrative look at the Universe’s past, starting when it was only half a billion years old. This far back in time, our Milky Way may have just formed. However, the Earth only made an appearance just under 8.5 billion years later.

The entire history of the Earth has taken place over just a third of the Universe’s lifetime – from the Earth’s formation, to the emergence of dinosaurs, early life, and humans – to the present day, where astronomers use Hubble to view some of the Universe’s earliest inhabitants and explore our origins.

9 Comments on "Hubblecast Video Explains How Hubble “Looks Back in Time”"

  1. So if all the information we have from the universe is based of how it looked in the past, billions of years in the past, how the hell can we tell that its expansion is accelerating when we don’t actually know what the universe is doing RIGHT NOW? All we know is what it was doing billions of years ago! Get your story straight cosmologist, you are not making any sense.

  2. This expansion of the universe has been studied for numerous years and even a small measurement of acceleration over that period is enough indication that it exists. Mr hubble was the man who brought our attention to the notion of expansion since the big bang theory and now they are determining its accuracy and speed. Objects accelerating at any rate without any force to stop them like friction will have to reach maximum speed before any negative direction in speed would be to happen. It would be nice if enough funds were available so that everyone could participate in these types of scientific activities. Do some research today and you could easily become one of the world foremost experts in 20-30 yrs time given your excelerated rate of learning compared to a caveman. Ofcouse you won’t get funding but still your knowledge and experience will be equally as important. Documentation is important should you discover anything yourself.

  3. I have a theory that says that we could look back at the earths history like looking in a mirror. Should there be a planet or object that reflects light back in this direction which all objects do. We should in theory be able to see all light that has left the earth as it bounced of its surface. The light reflects of the surface of the earth and then it reflects back in this direction from object millions of light years away. These are of course microscopic light measurements but the do exist. These light waves will be expanding so infrared light like james web or beyond might be needed but light will just keep on reflecting around the universe until it dissipates and loses all energy like in your house or unit. This could be used to look back through the history of the earth just like looking in a mirror which is just light reflecting of silver. To see through the clouds on the surface would require the same technology they are using to see through the universes dust and gas. I we can find planets by the light they are reflecting and so on this means it could be possible.

  4. Scientists ASSUME that the speed of light is constant. It is NOT. We have a constant only for calculations in and around our galaxy. What is misinterpreted as frequency, light is a series of photons travelling at varoius intervals. Also, time is constant. There is no such thing as time-space. RRG2013

  5. As a creator of a video, you have an obligation to make sure the captions are correct. You Tube provides automatic captions but the speech recognition software is not very good and the captions are unclear. Go to to look for the link that tells you how you can edit the captions. Please do this for your viewers who rely on captions. Thanks.

  6. The problem with science is that they do a lot of assuming and then the next day they say they have found new data when the fact is they didn’t know what they were talking about in the first place. Sure they are looking back in time because of the distance/time of light, but they have absolutely no idea how long that is. Science has yet to explain why the expansion of the universe is speeding up rather than slowing down or why the second law of thermodynamics is false. If you want any valid information that science has acquired, you had better come back to Earth and go to the lab because 99.99999% of everything else they say is wrong.

  7. If nothing moves faster than light, how did we get out here ahead of it to now be observing it as it reaches us. Very confusing if according to the Big Bang theory every thing started out in the same place.

  8. Madanagopal.V.C. | November 14, 2016 at 8:11 am | Reply

    Everything started on the same place at the time of Big Bang but they kept travelling in different directions. As the Universe grows, it has small babies, big babies, and adult galaxies as the time grows when these galaxies which were babies also grow and undergo metamorphosis. Our Milky Way Galaxy might not have been born then but only formed later from the nebulous cloud drifting apart which grew into our galaxy now. Hence looking at the distant past is true when Hubble peeps into very very distant galaxies.At 13.4 billion light year distance if any galaxy is witnessed it shows the film of the old form of that galaxy which will definitely not be in the same from at present. You get only the ancient photos of galaxies by observing them. It helps us to compare these photos with present day photos of our galaxies and nearby one and we see the metamorphosis. Expansion of the galaxies and the Universe is proved by the Doppler Effect of light wave received from the distant galaxies (Distant one are not stars anyway and definitely galaxies). The fact that they are thrown apart with extreme high force against their gravity forces calls for another very extreme force hitherto not understood namely the Dark Matter. Thank You.

  9. Extrapolated is that a powerful enough telescope will see the big bang occur. For now though I would like to know what the difference is between the light i see with my eye from stars vs the light seen at hubble. is it just the distance between me and hubble or is the telescope accelerating into the past against the spped of light

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