Why do astronomers believe that in the past galaxies were closer to each other than they are now?
Because they have been measured by red shift and other means to be moving away from us. The ones farthest are moving the fastest too.
Do you think humans will one day see other worlds beyond our galaxy Do you think it's possible to leave our solar system and explore other galaxies and see other planets or life forms big or small?
Collectively they are called Astronomers and Astrophysicists. Either professionals or amateurs. There are many types of astronomers, defined by how they study the stars. The most well-known are those that use optical telescopes followed closely by those that use Radio-telescope to pick up wavelengths other than visible light. there are many others and many other ways to collect data on the galaxies and stars. Astrophysicists are astronomers and may also collect direct data, yet they…
Why do galaxies expand primarily on one plane as oppposed to all planes ie a plate instead of a sphere?
Because galaxies don't expand. The universe expands. Think of galaxies as little spots on a balloon. When you blow it up the surface gets larger not the little spots, but the spots do get further apart. Gravity creates the extreme flatness that you observe. Moments after the big bang the initial structure of the universe was set, that applies to the size of the galaxies as well. The only observable difference is the galaxies were…
Most modern researchers believe that galaxies form as a result of two factors: the turbulence and properties of the gases around them, and how they have interacted with their surroundings throughout time. Irregular galaxies usually form the way they do because they have been affected by other nearby galaxies.
Probably, though most planets discovered so far - or perhaps all of them - are in our own galaxy. The reason for this is simply that it is easier to discover planets when they are relatively close to us. But, having discovered about a thousand planets nearby, there is no particular reason to believe that other galaxies would be devoid of galaxies. After all, the same laws of physics work in other galaxies as here.
Distances to other planets, other stars and other galaxies are very large, making measurements in meters or kilometers difficult to handle (although scientific notation can be used). As a result, astronomers have gotten accustomed to measure distance within the Solar System in astronomical units, and to other stars and galaxies, either in light-years or in parsecs.
Fairly averagely- it's a spiral galaxy of the larger sort, revolving slowly anticlockwise and of medium age as galaxies go. Our neighbouring galaxies are somewhat closer together in distance to each other than is usual, not exactly forming a cluster but making 'near neighbours' in galactic terms. There are many galaxies in the Universe that are far larger and older than our own Milky way, but also many others that are younger and smaller. Generally…