Category Archives: Galaxies

What is the Size of the Giant Galaxy IC1101?

Question: I’ve been looking at information about the largest known galaxy, IC 1101. Most sources say it is ~6 million light years in diameter but I can’t find any primary sources for this size estimate. I was looking through research … Continue reading

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The Kerfuffle Over Non-Cosmological Quasar Redshifts

Question:  Some years ago I read an article that said (if I recall correctly) that there were quasars that seemed to be associated with galaxies (maybe in the center), but the quasar’s much larger red shifts implied that their distance … Continue reading

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How Do Astronomers Study How Things Evolve?

Question:  We know that stars and galaxies we see are just fossil light as they were millions or billions of years ago. Is it possible to extrapolate the changes that we see today in those galaxies to determine their current … Continue reading

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Why Do Stars Form Preferentially in Spiral Arms?

Question:  Why most of the star forming regions/open clusters are in the periphery of galaxies(in spiral arms)?  – Vinod Answer:  Star forming regions are concentrated in parts of galaxies that contain high concentrations of the material from which stars are … Continue reading

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What is the Universe Expanding Into?

Question:  Thank you for helping so many people. Is there an educated guess by professionals about the difference between what the universe is expanding into and the universe itself?  – Jay Answer:  This is going to sound very paradoxical, but … Continue reading

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What if a Galaxy had Only One Star?

Question:  What if a galaxy only has 1 sun and 1 planet an it is in the exact middle?  – Lance Answer:  Galaxies are defined as collections of stars (possibly with planets), gas, and dust.  A single sun with a … Continue reading

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Can Gravitationally-Lensed Objects be Studied at Any Wavelength?

Question:  As per definition, Gravitational lensing refers to bending of light rays from a distant source around a massive object (Galaxy cluster) which tends to magnify the background light source. If visible light rays bend around those massive objects then … Continue reading

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Top Achievements for the NRAO Very Large Array

Question:  I’m embarrassed to ask this, as I feel after working here for so long I should already know the answer. But here it is: What are the top 3 discoveries/achievements of the VLA? And why?  — Doug Answer:  As … 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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How can a Telescope Image Both a Galaxy and the Stars within it?

Question:  How can Hubble give pictures with different zoom levels?  If telescopes are constructed with a fixed focal length and cannot “zoom”.  How come that Hubble can see individual stars in the Andromeda Galaxy http://www.spacetelescope.org/images/heic1112a/.  But can also see the … Continue reading

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