All Questions
35
questions
0
votes
1
answer
128
views
Do we really know the universal gravitational constant?
We've all heard $$F_g=\frac{gm_1m_2}{r^2}.$$ However, since I took physics, we've discovered "dark energy," which if I have any concept of the current thinking is caused by space being ...
1
vote
1
answer
68
views
Does dark energy work on the principle of anti-gravity, i.e. repulsive gravity?
Our universe is made up of 95% dark energy+ dark matter (of which most is dark energy), and this dark energy is considered to be the main reason for the expansion of our universe. But, anything that ...
1
vote
0
answers
44
views
Effects of dark energy in the kinetic energy of a body?
If I launch a ball into the sky it would reach a distance after which it would return into the ground transforming the potential energy into kinetic energy as it hits the ground
This is similar to ...
- 2,462
0
votes
1
answer
134
views
Theoretically, is it feasible for the dark matter density to be constant and homogeneous, as dark energy is, and the two to be related?
I know that currently dark matter and dark energy are separate things, not related and one not deriving from the other. But if both are included in a generalized gravitation theory, the picture can ...
- 1
12
votes
1
answer
1k
views
Is there a distance from a gravitational source where the influence of gravity and dark energy are balanced out?
While gravity is a force that attracts
objects with mass, dark energy (or, alternatively, the accelerated expansion of the universe) is not.
However, I have found numerous articles, forums, questions ...
- 2,462
1
vote
1
answer
97
views
Dark energy contributing to, or modifying, mass estimates?
I have found some papers (like this one: https://www.aanda.org/articles/aa/full_html/2009/45/aa12762-09/aa12762-09.html) which say that dark energy increases the potential energy in a system of a ...
- 2,462
2
votes
2
answers
87
views
Why the megaastrophysical objects do not collapse due to their gravitational selfattraction?
At the largest scale in the universe exist formations called filaments which form something like a spider web along the whole universe. But they seem to be quite static. So my question is about the ...
- 2,255
1
vote
1
answer
167
views
Could dark energy be explained via the use of a "gravitational charge"?
Could gravity be explained as the existence of a "gravitational charge", acting similarly to an electromagnetic charge but where like charges attract and opposite charges repel? A graviton ...
0
votes
1
answer
101
views
Dark Matter/Energy & Space-Time [closed]
After searching for quite a while for a minimalist approach to explaining Dark Matter as well as Dark Energy, unfortunately without much good, I decided I may as well help fill the explored paths, or ...
- 11
1
vote
0
answers
228
views
Is there a valid solution to Einstein's equations for this cosmological model?
The cosmological model below has been developed in order to explain the flatness problem.
At first it's from Newtonian considerations, then a solution of the Friedman equations is looked for
$$\left(\...
- 13.7k
5
votes
4
answers
374
views
Can gravity from a massive object outside our cosmological event horizon have any effect on Earth?
The gravity of a very massive luminous celestial object traveling at the speed of light away from us (at the Hubble Sphere) would have an Extremely small, but non-zero gravitation effect on Earth (...
- 143
2
votes
1
answer
136
views
Understanding the expansion of the universe
The universe is not only thought to be expanding but the rate at which it is expanding is said to be accelerating. Which of these models (if any) is a correct way of looking at this?
Model A:
Let’s ...
- 1,945
3
votes
1
answer
796
views
What exactly is the cosmological constant? [duplicate]
I know that the cosmological constant was developed as an addition to the Einstein Field Equation as an anti-gravity force: $$R_{\mu \nu} - \frac{1}{2} R g_{\mu \nu} + \Lambda g_{\mu \nu} = \frac{8 \...
- 2,162
1
vote
1
answer
58
views
Gravity and dark energy in space
I've been studying astrophysics and I read that our universe is still expanding because the gravity is not enough compared to the dark energy present. And right now we are not sure whether are ...
- 167
-1
votes
1
answer
54
views
Could a large amount of antimatter accelerate the universe instead of dark energy? [closed]
It is not known whether antimatter is repulsed by or attracted to matter. For the purpose of this question, I assume that antimatter is repulsive to regular matter (otherwise this question makes no ...
- 236