Galaxies

We will never have any accurate answer, for several reasons.

1. We're inside the Milky Way, and there is at least a third of it that is hidden from view on the other side of the galactic core. Estimates as to the number of stars in our galaxy ranged up to 400 billion stars, but that was just a guess.

2. In the last year or so, the estimates have more than DOUBLED, because we now think that there are vastly more of the very small and dim "brown dwarf" stars. We now estimate that there may be a TRILLION stars in the Milky Way.

3. Andromeda is a very long way away; the only individual stars that can be seen are the few very brightest stars such as supernovas. But because Andromeda is, we think, even larger than the Milky Way, an estimate of a trillion stars is probably quite reasonable.

The light of the Sun that we see today was actually emitted 8 minutes ago. Light travels at a fixed speed, of 299,800 kilometers per second.

The distances to even the closest stars, when measured in kilometers or miles, is an enormously large number. So scientists and astronomers measure stellar distances in terms of how long it takes for light to travel here. So even the nearest star, Proxima Centauri, is so far away that it takes light 4.2 YEARS to get here. So we express this as "4.2 light-years", or LY.

"kpc" is the abbreviation for kilo-parsecs. One parsec is approximately equal to 3.26 light years, so one kpc would be about 3260 ly.

In terms of the diameters of galaxies, we can at best come up with approximations. The distance to another galaxy is a matter of some conjecture, involving calculations of the relative brightness of "standard candle" stars, typically Cephid variable stars. As our understanding of the relationships between the mass, luminocity and the periodicity of a Cephid variable has evolved, our estimations of the distances has likewise changed.

I assume the same gravitational pull they share is from being sucked into an inward spiral, caused by a black hole in the center of both galaxies.... But then again, I'm no scientist or physicist... Just randomly studying the cosmos.

Yes, it orbits the galactic center.
The sun is one of billions of stars that comprise the Milky Way galaxy - a more or less flat circular disk of stars that rotates about it's centre. Therefore, the sun "orbit" the centre of the galaxy in a manner analogous to how the earth orbits the sun.

The Little Dipper is an "asterism" ... a recognizable pattern of stars that doesn't include the entire constellation ... in the constellation of "Ursa Minor" (the "Little Bear"). In most of the USA, the Little Dipper is visible at any time of any night of the year, in the northern sky. The end of its 'handle' is Polaris, the North Star, which appears to never move. The handle remains nailed to the North Star, and the dipper spins around it like the hand of a clock, once in 24 hours.

HD 140283 is the oldest star. Lately estimated to be 14.5 billion years old while the universe's calculated age is just 13.8 billion years old.

Of course it's not thought to be older than the universe. There are margins for error in the estimates of its age.

It also nicknamed the Methuselah star because it's the oldest known star.

Preparing the universe for a galaxy.

An elliptical galaxy, seen "face-on". (E7 would be "edge-on".)

I think it was only a fictional planet that they made on an episode of National Geographic's show called "Naked Science."

There are hundreds of billions of galaxies in the visible Universe; each of which might have, on average, hundreds of billions of stars. Astronomers don't just go around "discovering stars" - that would be as un-interesting as discovering grains of dust on a beach. Even more so, because problably there are more stars than grains of sand on a beach. Now and then, information about a star with some interesting property is announced - for example, extraordinarily young, hot, or big.

Jupiter is significantly larger than Earth, with a diameter approximately 11 times that of Earth. To put it in context, about 1,300 Earths could fit inside Jupiter. Jupiter's larger size contributes to its immense gravity and strong magnetic field.

In a galaxy, there are stars, the stars' planets, and the planets' moons. There are comets, asteroids, gas, dust, emptiness. You'll find nebula (star-forming regions) and black holes. In most galaxies, there is one supermassive black hole in the center that holds the entire galaxy together.

They orbit around the center of the galaxy due to the galaxy's own gravity. Contrary to popular belief, the Galaxy's central black hole does not have strong enough gravity to hold the entire galaxy together as it accounts for only a tiny fraction of our galaxy's mass.

someone is a little left back in the middle ages. The sun does NOT move.

Yes. Well, parts of it. If you look down, on the floor, you see planet Earth, which is part of our own galaxy; and all the stars and planets you see in the night sky are part of our own galaxy. Moreover, if it's dark enough, you can see a band of light, which is what gave our galaxy the name, "Milky Way".

They are shaped like a round galaxy and they are flat

Galaxy clusters typically have anywhere from 50 to 1,000 galaxies.

The other "solar bodies" are called stars.

Nebulae or star clusters within the Milky Way Galaxy.

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