Q & A
Acronym Guide
Further Reading
Outside the Site
Google Sky
Multimedia, Etc
Animation & Video
Special Features
Chandra Podcasts
Desktop Images
The Big Chandra Picture
High Res Prints
Screen Savers
Web Shortcuts
Chandra Blog
RSS Feed
Email Newsletter
News & Noteworthy
Image Use Policy
Questions & Answers
Glossary of Terms
Download Guide
Get Adobe Reader
Q & A: Galaxies, Galaxy Clusters, AGN, and Quasars

Galaxies   Galaxy (def.): Gravitationally bound collection of a large number of stars. The Sun is a star in the Milky Way Galaxy.

Field Guide to Galaxies & Active Galaxies
error-file:tidyout.logChandra Images: Quasars & Active Galaxies

Q: If the universe is expanding (because of the "dark energy" forcing things apart), then why do we see so many galaxies colliding with each other? Even the Andromeda Galaxy is going to collide with our very own Milky Way Galaxy.

Q: What sort of damage to the atmosphere of a planet could be expected from a direct hit by the 3c321 jet? Is the effect like being hit by a fire from outer space?

Q: It seems that anywhere one looks in the sky, one might be looking toward as many black holes (galaxies) as foreground stars (in our galaxy). Is this true?

Q: If the center of a galaxy is so much bigger and brighter than all of its stars, why is it that we cannot see the light it emits from earth with the naked eye; or, is it so far away that it only looks like another star in the night sky?

Q: How is it that objects with "jets" have such tight diameters?

Q: If two merging galaxies which are 10 billion light years away are observed on Earth now, does that mean that the galaxies have already merged?

Q: In the past has there been a news item that addressed the speed of distant quasars in relation to closer objects nearer to Earth?

Q: When our Galaxy collides with the Large Magellanic Cloud, how long will it take for the starbursts to die down, assuming the mass of the Large Magellanic Cloud is 1/10 the mass of our Galaxy?

Q: How long will it take for the M31 galaxy to merge with the M110 and M32 dwarf galaxies? How long will it take for a black hole in M32 to merge with the black hole in M31?

Q: Who was Abell 2125 named after and why?

Q: How does one reconcile the age of the Universe with extremely distant objects?

Q: How does one determine the masses from the temperature maps?

Q: How can we be completely sure that it's dark matter we're detecting in the Fornax cluster?

Q: Could galaxies represent embryo stages? To me some stages seem like human life cycles at birth. What happens to a planet if it were to be sucked into a black hole? Does it disapeer? What starts a black hole - supernova, planet burst, star burst?

Q: In a recent release from Chandra, you show a galaxy called C153. What if there were a human populated planet in this mess. Would they be in survivable conditions?

Q: If the Sun is moving through the galaxy at several hundred kilometers/sec. and the galaxy is also moving at about the same speed through the universe, could we send a spacecraft to a particular location "behind" us by causing it stand still with reference to the movement of the sun and the galaxy? Could we actually "stop" a spacecraft?

Q: In the recent Perseus image, I noticed (after enhancement) scan lines that are not obvious in the original. Given scan lines are concurrent with a radial gradient, what are the chances for moiré-like artifacts to arise that mimic structures suggestive of "sound waves"?

Q: I calculate the period for this wave in Perseus is over 9 million years and we cannot hear it.Why do you call it a sound as opposed to some specific astronomy-type that would refer to such low frequency waves?

Q: I was curious whether the X-ray telescope's designers anticipated its ability to capture images of sound waves (as in Perseus) and if the scientists were looking for these results when they requested the observation time?

Q: What is the uncertainty in the frequency of the sound discovered in Perseus?

Q: Regarding the story on Perseus, I thought that no information leaves a black hole. Light can't escape, so how can sound? Especially when the sound is generated from the black hole itself?

Q: Could the supermassive black hole in Perseus be a supermassive "white" hole? In the CXC image, the point is white, and in an X-ray photo, the white means that we can't pass the object?

Q: The CXC has imaged sounds waves in Perseus. What medium is modulated? While the waves are reported to be very low frequency, the implication is that there are areas of compression and rarefaction. Of what? The "ether" of space?

Q: Is there essentially no difference between spirals and elliptical's in their ability to create stellar mass black holes?

Q: I am quite interested in the X-ray photo of NGC 720 that is newly posted. Can you tell me what the 15 or so points of light are that show on the photo on the left and why they are not on the photo on the right?

Q: My question is what happens when two black holes with the same mass, size and everything encounter each other? Question two, what is a quasar?

Q: Where can I access details about the new discovery Q2345+007?

Q: Where can I find an image of the constellation Orion that also shows which nebula (or cluster, or whatever) is where?

Q: Can you tell me where I could find pictures of quasars? I am looking for one that is not strait.

Q: When I look at the picture of the Centaurus galaxy cluster at the web site, which part of the data below the image gives me a rough idea about how far this cluster is from the Earth?

Q: How do you define "furious rates"?

Q: What is the most distant object Chandra can see, and what type of object is it?

Q: When we say a halo of hot gas, what does that mean to me when I fly close to the galaxy and through the "Hot Gas Halo"?

Q: The image of the X-ray jet at and it's presumed hot spot appears to be a straight line (at least from our perspective). ... How can such a narrow beam maintain such a precise direction for such a long time?

Q: When will we see more quasars, AGNs, blazars,and polarization measurements from Chandra?

Q: Do galaxies really rotate counter-clock wise? Doesn't it depend on which side you are looking at?

Q: What is in the left part of the radio registration that is absent in the Chandra´s quasar PKS 0637-72?

Q: How many planet/planet collisions do you presume will come from the M31 incident to come--or do you think we will be smoothly assimilated?

Q: Our group is very interested in such outstanding phenomena, like that in Centaurus A. We would like to receive more facts and information about this (pure scientific info.: mass of the star, radius of the star, distance from Earth, type, etc. ).

Q: I was looking for quasar 3C273 with the light jet going ten times the speed of light, but could not find the image on this site. Do you have any suggestions?

Q: 3C295 is five billion light years away. However, I read an article which mentions an event at 3C295 that happened one million years ago. How can this be?

Q: How can gases maintain temperatures of millions of degrees in the "void" of interstellar and intergalactic space for extended periods of time?

Q&A Index