there are many theories as to what forms first, and they aren't 100% certain still. But one theory suggests that the disk galaxies form around a large gas cloud which then gravity pulls it to create the arms around.
They have used up most of their interstellar matter, so then they have very little star formation going on. This leaves them with the same aging stars.
being on retrograde orbits just means that they are orbiting the opposite way of the Milky Way. The other clusters would be moving the same direction that the milky way is orbiting.
Our milky way is about 100,000 light years in diameter, which is huge for us. But compared to a couple other galaxies there is M87 which is an elliptical galaxy and this one is 980,000 light years in diameter. Then there is Hercules A which is 1.5 million light years across. So there are other galaxies out there that are much bigger, but we aren't the smallest one either.
Why are some spiral galaxies barred and others not? For instance does it just happen or is there something specific in the formation of the galaxy that makes it that way?
The bars contain mostly stars where as a spiral contains gas and dust with a few stars. The reason behind why some have bars and others don't is still being researched, but some theories are how tight the spiral arms are being pulled (bar or bulge), and another is that the gas is centered where the bulge would be but then it is sustained and pulled a different way by the same density waves.
Has the black hole always been super massive or was it ever smaller?
ReplyDeletethere are many different sizes of black holes, they can be massive but they can also be very small.
DeleteWhich part of a galaxy usually forms first?
ReplyDeletethere are many theories as to what forms first, and they aren't 100% certain still. But one theory suggests that the disk galaxies form around a large gas cloud which then gravity pulls it to create the arms around.
DeleteWhy do Lenticular Galaxies contain mostly aging stars?
ReplyDeleteThey have used up most of their interstellar matter, so then they have very little star formation going on. This leaves them with the same aging stars.
DeleteHow come only 40% of the Milky Way's clusters are on a retrograde orbit instead of all of them?
ReplyDeletebeing on retrograde orbits just means that they are orbiting the opposite way of the Milky Way. The other clusters would be moving the same direction that the milky way is orbiting.
DeleteRelating to size (mass and volume), how does the Milky Way compare to other galaxies?
ReplyDeleteOur milky way is about 100,000 light years in diameter, which is huge for us. But compared to a couple other galaxies there is M87 which is an elliptical galaxy and this one is 980,000 light years in diameter. Then there is Hercules A which is 1.5 million light years across. So there are other galaxies out there that are much bigger, but we aren't the smallest one either.
DeleteWhy are some spiral galaxies barred and others not? For instance does it just happen or is there something specific in the formation of the galaxy that makes it that way?
ReplyDeleteThe bars contain mostly stars where as a spiral contains gas and dust with a few stars. The reason behind why some have bars and others don't is still being researched, but some theories are how tight the spiral arms are being pulled (bar or bulge), and another is that the gas is centered where the bulge would be but then it is sustained and pulled a different way by the same density waves.
DeleteWhy do spiral arms contain higher densities of interstellar gas?
ReplyDeletespiral arms contain many young blue stars which makes the density higher and the arms brighter.
Delete