Questions regarding the space in which all mass is thought to exist.

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15
votes
3answers
2k views

What's the fastest moving object in the universe?

We know that nothing can have proper velocities larger than the speed of light in vacuum. But are there any objects in space that get close to it? Any comets, or other objects thrown by gravity or ...
8
votes
1answer
167 views

Why does a planet rotate and revolve?

Why do planets rotate and revolve in the universe?
3
votes
1answer
116 views

Does our universe have to be embedded in a higher dimensional space?

I've heard that our universe may be open or closed. If it's closed it might have a toroid shape. If this is the case, would that imply that our 3 spatial dimensions have to be embedded in a higher ...
9
votes
7answers
422 views

What's the largest non-spherical astronomical object in the universe?

Some asteroids and comets are non-spherical. But is the nature of big things and gravity so that large things in the universe are always spherical? What is the biggest astronomical object in terms of ...
9
votes
1answer
98 views

On what scale does the universe expand?

According to the theory (or my understanding of it), the universe is not only expanding, but speeding up. If the galaxies are moving apart, are the solar systems within them also moving apart from ...
6
votes
2answers
139 views

Is there any difference between parallel universes and multiverse?

Nowadays we come across with these two terms - parallel universes and multiverse. I wonder if this is the same thing or its two entirely different principles because the names are a bit confusing to ...
4
votes
2answers
107 views

How does light affect the universe?

When light is emitted by for example a star, that star loses energy - which causes it to reduce its gravity. Then that energy begins a journey for potentially billions of years, until it reaches some ...
3
votes
2answers
221 views

What is the physical, geometric shape of the universe?

I'm not asking about theoretical ball, vs saddle, vs flat surface which is just a metaphor with 2D space. It's hard to say as we see very little of it, and we see them in the past because light ...
2
votes
2answers
92 views

Has life been discovered outside of Earth?

I've just watched a movie that made me curious as to whether life has really been discovered on another world such as Europa??