Galaxies, rather than stars!

by Yadirf 24 Replies latest jw friends

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  Yadirf

  Thanks to ALL that replied in this thread ... much information to think about. I have to be out of town today, and so any comments I make will have to wait until tomorrow.

  I did want to reply to something Amazing said though, before I leave:

  You said that stars cannot be seen outside our Galaxy. This is not accurate. If we can see other Galaxies, such as the nearby Andromeda, we can see some stars in that Galaxy. The reason we do not see individual stars outside our Galaxy is that they are not there. Stars only cluster into Galaxies.

  I think if you will go back and review what I said, Amazing, you'll find that we say pretty much the same thing. I said: "There are no stars outside our galaxy that can be seen at all. Stars outside our galaxy would be stars inside OTHER galaxies, and of course aren't individually viewable through even the most powerful telescopes. The most powerful telescopes are unable to even detect OTHER PLANETS...which are part of our galaxy....so it's understandable that although other galaxies themselves can be brought into view the numberless individual suns (stars) that comprise those galaxies cannot be discerned."

  With regard to you having said, "If we can see other Galaxies, such as the nearby Andromeda, we can see some stars in that Galaxy", I plan to search for a large photo of that very galaxy which I bought at a Planetarium, quite some years ago, that I have stored away here somewhere at the house. If some of the individual stars that make up that galaxy can indeed be seen/distinguished, the photo I have will show it. So, you very well may be right, and my memory has just faded. Of course, there has to be some way for knowing that galaxies are constructed of stars.

  Thanks again, everybody.
  Yadirf

  Daniel 11:35 ... a KEY prophecy that must be fulfilled before the "time of the end" gets underway.
• 

  AlanF

  FunkyDerek, David Gladden and Amazing summed things up very nicely, but I'll add a bit.

  Normally, individual stars in other galaxies can't be seen directly because they're too faint. However, when a star goes supernova the galaxy it's in appears to brighten considerably. A brightening of galaxies can also be seen in nearby galaxies when Cepheid variable stars in them brighten and dim. These variables have a special spectral signature that was first observed in Cepheids in our own galaxy, and when the same signature is observed in the brightening of other galaxies astronomers properly conclude that they're observing Cepheids in them. By doing statistical analyses of Cepheids in our galaxy and in nearby galaxies, brightness comparisons allow astronomers to make estimates of the distances from ours to the others. These estimates appear to be good, but not written in stone. During the last decade some astronomers have revisited the various assumptions and observations with respect to these estimates, and have found that earlier estimates were too small by a factor of 1.5 to 2. Thus, the distance to the Andromeda galaxy has been revised from a bit over a million light years to about two million. This means that the universe appears to be nearly twice as big as earlier estimates pegged it.

  Planets around other stars certainly cannot be observed directly, but recent observations using indirect techniques appear to show that they do exist. One indirect technique works this way: When a planet orbits a star, what actually happens is that the planet and star orbit each other. Because the star is much bigger than the planet, the motion of the star is much smaller than that of the planet, and so by convention we say that the smaller object is orbiting the larger. When the plane of the orbit of a planet is roughly in our line of sight, the star appears to recede from us during half of the planet's orbit, and to move toward us during the other half. Due to the Doppler effect, this motion affects the star's spectrum in a cyclical fashion. Astronomers can observe the spectrum over a period of time and observe periodicities in how the spectrum changes. They then know that some large object, perhaps a dim star or a very large planet, is orbiting the star. With other techniques that I'm not up on, they can more or less tell whether the smaller object is a dim star or a large planet. These days astronomers are finding that quite a few stars appear to have large planets orbiting them. These planets appear to be much larger than Jupiter, some almost large enough to have ignited and formed a star. Astronomers are beginning to conclude that there are a lot more of these huge planets than they had thought, and that there is a continuum of sizes of objects that condense from interstellar gas and dust into planets and stars. Indeed, the only difference between stars and planets is that planets were too small to ignite and become a star. This is consistent with the fact that there are so many double and even higher multiple stars out there.

  Yadirf, you need to get a good astronomy book from the library. It will tell exactly how astronomers figure all this stuff out.

  AlanF
• 

  Fredhall

  It doesn't suprise me that AlanF have to ADD his three cents to this post.
• 

  Mindchild

  I just thought I would add a few additional comments here of my own on this thread as I love astronomy and have owned some really great telescopes before.

  First, most people have no clue as to how huge the universe is. With a modern telescope, you can take an area of sky about the size of a quarter held at arms length, and in that tiny section of sky you can actually see over a million galaxies, each of those having hundreds of millions of stars.

  I believe that I have read somewhere that astronomers have discovered stars outside of our own galaxy that are not associated with any nearby galaxy. These are some old globular clusters.

  Something else quite interesting about galaxies is that the rotating spiral shape so commonly associated with galaxies shows evidence of something quite interesting, namely huge amounts of dark matter that keep the outer stars from flying off into deep space. There are also incredibly large monsterous black holes in the center of many galaxies, including our own Milky Way, that have eaten hundreds of thousands of stars for lunch. These are like the sharks of the ocean and gobble up any nearby stars.

  The universe is an very large and interesting but deadly place.

  Skipper
• 

  Yadirf

  After having been alerted to the fact that the links I provided in my first post up above aren't working, I then remembered having received the following notification:

  Homestead will be performing a major system upgrade to our servers on Monday, January 21st that should last approximately 48 hours.

  So, it appears that the links won't work before Wednesday probably. Sorry for that, and hope that you will check back.

  Yadirf
• 

  Yadirf

  Looks like Amazing was the most correct regarding whether or not individual stars of other galaxies can be seen/distinguished.

  If we can see other Galaxies, such as the nearby Andromeda, we can see some stars in that Galaxy. - by Amazing

  Stars outside our galaxy would be stars inside OTHER galaxies, and of course aren't individually viewable through even the most powerful telescopes….the numberless individual suns (stars) that comprise those galaxies cannot be discerned…. - by Yadirf

  Normally, individual stars in other galaxies can't be seen directly because they're too faint. – by AlanF

  That some individual stars of the Andromeda galaxy can in fact be seen is attested to here in a January 17, 2001 report regarding this very question, I found on the Internet:

  Studying Individual Stars In Andromeda Galaxy Bulge
  An individual team including an astronomer from the Observatoire de Paris has recently observed for the first time individual stars in a very dense zone of an external galaxy, enabling for the first time an eagerly awaited comparison with the corresponding zone of our galaxy, the Milky Way.
  With the advent of the refurbished Hubble Space Telescope (HST), it has become possible to study individual stars at the distance of the Andromeda galaxy (Messier 31). Resolving stars at still greater distances will require the next generation of ground- or space-based telescopes.

  Click here to read the rest of the story: http://unisci.com/stories/20011/0117015.htm

  Yadirf
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  Yadirf

  Although one might think so before realizing it, NONE of the individual stars seen in the image below lie within the vicinity of the galaxy itself, not behind or around it as it might appear without knowing otherwise. A person is in reality looking through a massive number of stars which reside in our Milky Way galaxy, and seeing the Andromeda galaxy in the distance.

  For those who may be interested, here's a little info regarding the location of the Andromeda galaxy, taken from The American Heritage Dictionary:

  An·drom·e·da 1. Greek Mythology. The daughter of Cepheus and Cassiopeia and wife of Perseus, who had rescued her from a sea monster. 2. A constellation in the Northern Hemisphere between Lacerta and Perseus and south of Cassiopeia. It contains a large spiral galaxy visible to the naked eye. The spiral is 1.84 × 105 light-years from Earth.

  The Andromeda Galaxy
  
• 

  VeniceIT

  "The Galaxy is on Orion's Bbbbbbelt"

  "Hey that's what the lil dude in the big dudes head said."

  Ven

  "Injustice will continue until those who are not affected by it are as outraged as those who are."
• 

  julien

  Some stars have been found outside of galaxies:

  http://antwrp.gsfc.nasa.gov/apod/ap020119.html
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  Yadirf

  Thanks for coming up with that, Julien. – Yadirf.
  ====================

  Stars Without Galaxies
  llustration: J. Gitlin

  Explanation: Galaxies are made up of stars, but are all stars found within galaxies? Using the Hubble Space Telescope, researchers exploring the Virgo Cluster of galaxies have found about 600 red giant stars adrift in intergalactic space. [Below] is an artist's vision of the sky from a hypothetical planet of such a lonely sun. The night sky on a world orbiting an intergalactic star would be a stark contrast to Earth's - which features a spectacle of stars, all members of our own Milky Way Galaxy. As suggested by the illustration, a setting red sun would leave behind a dark sky flecked only with faint, fuzzy, apparitions of Virgo Cluster galaxies. Possibly ejected from their home galaxies during galaxy-galaxy collisions, these isolated suns may well represent part of a large, previously unseen stellar population, filling the space between Virgo Cluster galaxies.
  .