@NickMinaj69
Search for "hypervelocity star" and you'll find lots of material. In particular, there'll be a hit on hubblesite for "Hyperfast Star Was Booted from Milky Way" about a star designated HE 0437-5439. You may also be interested in a search for "intergalactic globular cluster" -- entire globular clusters that roam between the galaxies. NGC 2419 *may* be one, in fact (there is some doubt).
@pseudorandomly I wasn't following the conversation, just read this one comment. Do you know the name or where I can find further information about the lone star in the Local Group? I'm curious, I've never heard of this before, I'd love to know more.
@NickMinaj69
You are mostly correct, but not completely. Galaxy collisions can draw out long tidal tails, from which it is possible that individual stars could escape altogether. In addition, it is *known* that stars can be ejected from a galaxy by gravitational interactions near the core; not only is this possible in theory, but we have observations of at least one such runaway star in the Local Group that belongs to no galaxy.
@NickMinaj69
I'm not sure you're following the point of the conversation we were having. The OP was confused about "object", "galaxy", and "supernova" in some manner that I was unable to fully understand. I was postulating an isolated star in an attempt to figure out the source of his confusion.
@pseudorandomly The only starts "not in galaxies" are globular clustarts, which exist in galaxy halo's. Which are in the vicinity of galaxies, but a star just sitting in space, not orbiting a galaxy, is non-existant
@pseudorandomly Because stars do not exist if not in part of galaxies. The only way to be formed is by the compaction of molecular clouds (which only exist in galaxies) and once they are formed, they are trapped by the gravity of the massive black hole in the center.
@bandet888
I confess to not understanding your confusion. Suppose this supernova was a star sitting out in space all by itself, not part of some galaxy. What possible difference could that make?
@pseudorandomly Yes I do see what you're saying. It's just that this video claims this to be the most distant object (meaning one object I guess) but doesn't say anything about being in another galaxy. But you may be right.
@bandet888
Think of it like this -- put a collection of light bulbs in a glass box and turn them on. Now place the glass box a long distance away; so far that you can barely, if at all, detect the lights. Now set off one large flashbulb in that box. Originally, you see the box as a tiny faint blob of light, if you detect it at all. Then the flashbulb goes off and suddenly the box appears *hugely* brighter, even though just one bulb is responsible for the brightening.
@bandet888
Not precisely. What I'm saying is that there is probably an agglomeration of stars there (whether it qualifies as a "galaxy" at that young age is a matter of interpretation). What has happened is that a single star in that agglomeration has gone supernova, creating a gamma-ray beam that happened to point in our direction, which we see as a gamma-ray burst. This object is a single star; the whole *galaxy* isn't brighter, just the supernova within it -- the other stars are unchanged.
@pseudorandomly I get what you're saying. But I'm still under the impresion that this video is claiming that this object is a single star. Are you saying that this object is an entire galaxy that's brighter because of a supernove star?
@bandet888
It's all about brightness. Gamma-ray bursts can, for a short time, be the brightest objects in the entire Universe if you happen to be within the path of the beam. So if a star in a very distant galaxy goes supernova and beams a gamma-ray burst at us, it can be easily visible all the way across the Universe.
When the light is very faint, there are other related features in the spectrum that we can use rather than looking for individual lines which may not show up in very dim objects. This gives us a somewhat less precise, but still reasonably well-determined distance.
@david90759
That takes rather a lot of explaining. Briefly, we can tell how far away distant objects are by measuring how fast they are moving away. We split the light from the star into its constituent colors (called a spectrum), and note the positions of dark lines in that spectrum that correspond to absorption from known elements such as hydrogen. The position of these lines changes with speed; we can calculate the corresponding speed and relate the speed to the object's distance.
@bandet888
Sorry, but you're simply wrong about this. A supernova can in fact be brighter than the center of the galaxy; it can briefly outshine the entire galaxy it inhabits (unless the galaxy is exceptionally bright). The sudden brightening of a distant galaxy, such as in this case, is easily explained by the supernova explosion of a single star. In this case, the exposure is simply not long enough to capture the light of the containing galaxy.
@club4ghz I don't think a supernova star would be brighter than the center of the galaxy. Even if it is when you look at a distant galaxy you see the WHOLE galaxy! This video claims this to be a single star! There are no cluster of stars around this object. A single point of light could be either a star or a distant galaxy. But you cannot see just one star in a distant galaxy. Maybe this is the most distant star in our own galaxy but cannot be just one star in a distant galaxy.
@club4ghz This video shows this object as a single star. When you look at a distant galaxy you see the center plus a cluster of stars around it. there's no way to single out one star from a distant galaxy let alone the most distant galaxy. Not with our telescopes anyway.
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