Category Archives: Galaxies

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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Detecting a Galaxy Cluster With a Radio Telescope

Question:  Is it possible for a 7-m radio telescope to detect a galaxy cluster of redshift below 0.03? – Ungku Answer:  Yes, as long as the cluster is big and bright enough at the radio frequency at which you want … Continue reading

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How Did the First Galaxies Form?

Question:  From where did this initial cloud of gases and dust come? In other words, how did the cloud form? Why were these gases and this dust together in a cloud? I read on another website that the cloud began … Continue reading

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The Andromeda Galaxy’s Orientation Relative to Us

Question: Do you know if there is current agreement about which edge of the Andromeda galaxy (M31) is closest to the Milky Way?  I don’t believe present distance measurements are precise enough to distinguish the near and far sides with … Continue reading

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Can a Black Hole Swallow a Galaxy?

Question:  I know that black holes are very dense and their gravitational pull is so strong no one really knows what they look like because they don’t come out alive. I have read that there might be one in the … Continue reading

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The Solar System’s Rotation About the Center of the Milky Way

Question:  I have a question about galaxies, how do scientist know about the galactic year and how long it takes? Well people think that are universe is only 14 billion years old has our solar system gone through a galactic … Continue reading

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The Properties of Spiral Galaxies, Including Our Own

Question:  Me and the rest of our fifth grade class is learning about galaxies, but I have a couple questions. Why is the middle of a spiral galaxy bigger than the arms? How fast is our Galaxy moving, is it … Continue reading

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