How do astronomers observing distant galaxies talk about looking backward in time?

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The speed of light is not infinite. Light takes time to travel from distant galaxies to our eyes here on Earth. If a galaxy is 1 billion light years away, it has taken 1 billion years for the light emitted by said galaxy to reach us here, so (obviously) we are seeing the light emitted 1 billion years ago. In a sense, we are seeing 1 billion years into the past at the light emitted by that galaxy.
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Why do distant galaxies look like stars?

Because they are so far away that the light is too dim and diffuse to make out individual stars or groups of stars. With a high-powered telescope, you can distinguish other ga

Why can astronomers learn about the past by looking at distant galaxies?

The light of those distant stars and galaxies took an appreciable period of time in getting here to be detected in our telescopes. So when we look at distant galaxies, we're s

Explain why looking at distant galaxies give scientist an idea about how galaxies change over time?

There are many stars in each stage of development, so the obvious assumption is that they represent similar stars, with similar stages, except that they began their existence

How is observing distant astronomical objects like seeing back in time?

Picture this: You and your best friend are in constant communication, and your friend constantly informs you of every little thing that happens in her life. But the method o

What can astronomers conclude based on the observed red shifts in the spectral lines of distant galaxies?

The strongest consensus (near unanimous of the astronomical community is that the redshifts of distant galaxies indicate that all distant galaxies are receding from us. This
In Red Shift

How did 1920's astronomer Edwin Hubble explain his observations that all light from distant galaxies exhibits the red-shift Doppler effect?

He concluded that all of space was expanding. Answer2: Hubble did not conclude that all space was expanding! Hubble concluded that he did not know what the redshift was.