Category Archives: Cosmic Distances

Why Can We See Stars That Are Billions of Light Years Away?

Question:  I can’t get seem to find a thoughtful yet scientific answer to this question, I was hoping you could help.  I hope this doesn’t sound dumb, I don’t mean it to be.  When we look at the night sky, … Continue reading

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Are Quasars and Radio Galaxies the Same Thing?

Question:  I’m interested in the differences and similarities between radio galaxies and quasars. Different sources say different things. Are radio galaxies just quasars with the “jets” pointed away from us, or are there other differences between them?  – Steve Answer:  … Continue reading

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What is the Difference Between the Redness of an Object and its Redshift?

Question:  What is the difference between Doppler shift of light and Natural light spectra (blue for young and red for old) with respect to stars and galaxies? How does astronomers differentiate between Doppler shift and Natural light spectra of deep … Continue reading

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The James Webb Space Telescope and Cosmology

Question:  As per current observations mostly from Hubble telescope and its deep field view, that universe is accelerating much faster at its observable edges, which forms the basis for Hubble constant and the age of the universe. Will the age … Continue reading

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How Light Travel Time Affects What We See

Question: If the sun disappears it would take us 8 min. to realize it.  How in the world, what we are seeing in telescopes are still existing?  What we are seeing is light that has been traveling minutes, hours, thousand … Continue reading

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How Do Astronomers Measure the Size of the Universe?

Question: I’m 15 years old. I want to know how do scientists measure the size of universe or observable universe.  – Hassan Answer:  There are several techniques that astronomers use to measure distances in the Universe.  Most of these distance … Continue reading

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