Questions tagged [universe]
Questions regarding all of time and space and its contents.
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Does the Milky Way move through space?
Does our galaxy moves through space? Or does it stay in a single location? If it does move, what causes it to move?
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Is there a star over my head?
Say I'm standing up straight, and I draw a straight line from my core through the top of my head (perpendicular to the ground). What is the probability that that line intersects with a star?
EDIT: I'...
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What is in the center of the universe?
If the universe has formed & originated by a Big Bang Explosion, then there must be empty space left in the center of the explosion site, as all the matter is travelling at tremendous speeds away ...
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How can 'HD 140283' be older than the universe?
Scientists have known about the star HD 140283, informally nicknamed the Methuselah star, for more than 100 years, since it cruises across the sky at a relatively rapid clip. The star moves at about ...
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How do scientists know that the distant parts of the universe obey the physical laws exactly as we observe around us?
How do scientists know that distant parts of the universe obey the physical laws exactly as we observe around us?
The question might look a bit odd but I am really stuck on my head. We know, ...
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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 ...
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Why is the observable Universe larger than its age would suggest?
The age of the Universe is estimated at 13.8 billion years, and current theory states nothing can exceed the speed of light, which can lead to the incorrect conclusion that the universe can't have a ...
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Age of the universe and time dilation
Given our knowledge and the standard cosmological model, we estimate that the age of the universe is about 13.7 billion years old.
How much sense does it make to talk about the age of the universe as ...
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Are there more stars in the universe than grains of sand in the Earth?
My ten year old daughter asked me this question at breakfast and I initially said yes, but on second thought I was also puzzled.
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What exactly is the "paradox" in Olber's Paradox?
To the extent of my understanding, Olber’s paradox states that if the universe was static and homogeneous, we should see a star at every point in the night sky and therefore the night sky should be ...
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What would happen to a polished marble statue left in space for a million years?
Consider it doesn't collide with any other objects. Would it be preserved perfectly in the vacuum or would its surface be damaged by anything like UV rays, radiation, gas, space dust, etc?
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Is there any practical use for astronomy?
Although astronomy is very cool and the things we are learning are awesome, is there really any practical use to knowing the things we know about the universe?
Do other fields of science draw from ...
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Does the recent news of "ten times more galaxies" imply that there is correspondingly less dark matter?
Nature: Universe has ten times more galaxies than researchers thought
NASA feature: Hubble Reveals Observable Universe Contains 10 Times More Galaxies Than Previously Thought
Headlines sometimes ...
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Explaining Dark Matter and Dark Energy to layman
With my little knowledge, I know this:
Dark Matter
The center of a galaxy controls/attracts its objects (stars, planets, comets etc.) towards itself because of gravity. But the mass of the center of ...
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What equation tells you how far in space you can go from a point and return?
We know that hubble expansion increases the distance between points in space, and that the cosmological event horizon represents the distance from the observer at which objects are receding faster ...
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How many sun-like stars are there in the universe?
After yesterday's announcement of the Kepler telescope finding a huge amount of newly observed exoplanets, i saw a headline claiming that as much as 22% of sun like stars in the universe have planets ...
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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 ...
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How can the 13.8 billion years old universe have a radius of 46 billion light years? [duplicate]
The universe is about 13.8 billion years old. Assume at the big-bang it starts from a small region and the maximum possible speed according Einstein is the speed of light how can the universe got a ...
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How can the universe be infinite?
I've heard from renowned astrophysicists that we don't yet know whether or not the Universe is infinite. How is that possible regarding the big bang theory is accepted (as they all do)? Are they ...
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Are there any alternative explanations for the gravitational force we attribute to dark matter?
It always seemed counter-intuitive to me that we observed an measured a gravitational force and since the universe has not enough mass to account for it, the conclusion was to say there's a different ...
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Can any information leave a black hole?
Referring to this question, is there any information that can leave black holes? Are they causing a permanent information loss in our Universe?
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Can there be planets, stars and galaxies made of dark matter or antimatter?
We know that the universe has more dark and anti matter as compared to normal matter. Can there be dark matter galaxies or antimatter galaxies?
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How do we know we're not getting bigger?
Alright so I've been thinking a lot about how the universe expands and I've always wondered if we're getting bigger as well. Since everything would be getting larger at an equal rate (tools of ...
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What is the most dense object in the universe?
Inspired by this answer to the question, Why is the Sun's density less than the inner planets?, what is the most dense object in the universe?
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Will there be collision between universes?
I just watched one of those videos that shows the scale of the universe, zooming out from one thing all the way out to the sphere that is thought to be the universe. However, they also showed other ...
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Will we start seeing galaxies disappear due to Universe expansion? [duplicate]
Does the fact that universe is currently expanding at an accelerating rate means that far far away objects (FAO) might start disappearing with time, set aside the "red shift"?
I'm saying this ...
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Do parallel universes exist?
Do other universes like ours exist?
If they exist, how do we know that they exist when we have even not seen the ends of our own universe?
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Layout of the universe
I've been working on a space game in my spare time, and lately I've been thinking on how to lay out the universe. Though I've searched around and found it hard to get a good view of what the universe ...
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Why black holes are extremely cold?
"The most massive black holes in the Universe, the supermassive black
holes with millions of times the math [sic] of the Sun will have a
temperature of 1.4 x $10^{-14}$ Kelvin. That's low. Almost ...
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Observable universe equals its Schwarzschild radius (event horizon)?
The estimated age of the universe is 14 billion years.
The estimated Schwarzschild radius (event horizon) of the observable universe is 14 billion light-years.
What are the ramifications?
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How exactly is our universe mapped?
Watching this youtube video shows that our planet is nothing more than dust in the wind.
At the 2:50 mark in the video, you will see a view of the whole Milky Way. At the bottom you will see this ...
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How are Galaxy Super Clusters Generated
I have seen pictures of clusters of galaxies, usually used in regards to theories of dark matter and galaxy formations. One of the most famous ones has the perceived shape of a stick-figure. If I am ...
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Where is all the antimatter?
The universe supposedly started off with equal parts matter and antimatter and they are said to annihilate each other. Also, nature is famous for it's balance between everything. So all we see is ...
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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 ...
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Are there ways to estimate size of the "whole universe"?
Words escape me, but by "whole universe" (I think) I mean everything that's spatially connected to the observable universe in a conventional sense. If there is a better term for it, please let me know!...
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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 ...
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When the universe expands does it create new space, matter, or something else?
I am wondering what exactly is meant when it is said the universe expands. Does it simply create new space for matter to fill, does it also create new matter/dark matter to fill that space, or am I ...
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Does the mass of the observable universe ever change?
First do we have anyway to even estimate the mass of the entire observable universe? And then is there any data that shows mass being gained or lost? Would we ever know if someone was playing with ...
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Is the earth bombarded equally in all directions by neutrinos?
Perhaps it is hard to known for sure because neutrinos are very difficult to detect, although they do go through the earth in very large numbers. But are they passing through the earth equally from ...
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How does the concept of a universe with no center work?
I understand basically that the universe is homogenous (looks the same from every point) and I was told in my astro class that it's supposed to have no center, but how that works boggles my mind. I ...
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is there any theory or observational evidence that our universe is electrically neutral or not?
It seems our universe is neutral in large scale.
There is CP violation (wiki) problem with respect to matter and antimatter.
Similarly is there any theory about whether our universe is electrically ...
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Why does it make sense to say the universe has no centre?
If we suppose we and everything in the universe is perfectly flat. That is, we have width and depth, but no height. And we are situated on the surface of a balloon blowing up with air and expanding "...
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Are there only $10^{83}$ atoms in the universe?
I'm a high school junior. I assumed there would be an incredibly huge number of atoms in the universe if not infinite. Recently, I've come across a few articles which claim that scientists believe ...
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Are there some (simple) mathematical models which can simulate the cellular/web structure of the universe?
To visualize the structure of a solar system we have some simple mathematical model: Planets orbiting around a Star in circular motion.
If we want to be more precise the circle becomes a ellipse, the ...
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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 ...
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Does the CMB pattern evolve in a human lifetime?
I was thinking, as CMB is a snapshot of a slice of the Universe during recombination, how much the cmb is changing with time ?
I mean as we progress in time we look a CMB a bit more faraway each time, ...
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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 ...
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What are the stages in the life of a universe?
Geological periods describe varying phases in the last few hundred million years on earth.
Are there any names for the periods on a timescale 1-2 orders of magnitude greater, that is, for the stages ...
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Is the age of the universe relative to an observer's location in that universe?
According to Wiki the age of the universe is 13 billion years old, and I was taught that background radiation made the universe uniform in all directions.
Doesn't this define a sphere of space in the ...
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