Exploring the Nature of Dark Matter and Its Effects on Galaxies

In summary, dark matter has been tentatively discovered, and it may be composed of three phases. Some people believe that ammonia tank detectors may have detected dark matter, but the evidence is still inconclusive.
  • #1
30
0
if there is dark matter every where, why it is noticed near galaxies? why can't we do some very sensitive lab experiments of gravity to find the effect of dark matter?
 
Physics news on Phys.org
  • #2
jayaramas said:
if there is dark matter every where, why it is noticed near galaxies?

Because there is more of it near galaxies. Or rather, the galaxies themselves form where the dark matter clumps together under its own gravity, because the gravity of the dark matter causes normal matter to "pool" there as well.

jayaramas said:
why can't we do some very sensitive lab experiments of gravity to find the effect of dark matter?

Because it isn't very dense. Sure, most of the mass of a galaxy is probably in its dark matter halo, but it doesn't appear to clump into dense objects like stars and planets. When you spread out all that mass across the vast amount of empty space available in and around a galaxy the density becomes much too low for one to notice any local gravitational effects that might exist.
 
  • #3
Jay, consider a very large cloud of Hydrogen gas in the galaxy. The combined mass of this gas is easily 1000 times more than our Sun. As you are passing through this cloud you would barely be able to detect the gravity because the density of the cloud is very small and it is all around you. Only by measuring things such as a star passing by the cloud would you notice the gravity because it is being pulled towards you. Similarly dark matter is spread out all around the galaxy instead of being clumped together, so we have a very difficult time detecting it within our own galaxy. When we look at other galaxies we can see the large scale effect because we are outside of that galaxies dark matter and can see things such as gravitational lensing and the rotation of the stars in the galaxy.
 
  • #4
Has dark matter been tentatively discovered?, is it 3 phase? Can someone confirm what I read about the ammonia tank detectors a while back?
 

1. What is dark matter and how is it different from regular matter?

Dark matter is a type of matter that does not emit or absorb light, making it invisible to telescopes and other instruments that detect electromagnetic radiation. It is thought to make up about 85% of the total matter in the universe, while regular matter (the kind we are familiar with) makes up only about 15%. Unlike regular matter, dark matter does not interact with electromagnetic radiation, which is why it is difficult to detect and study.

2. How do scientists study dark matter?

Scientists use a variety of methods to study dark matter, including observations of its gravitational effects on visible matter, computer simulations, and experiments with particle accelerators. One of the most common methods is to study the rotation curves of galaxies, which can reveal the presence of dark matter based on how the stars and gas in a galaxy are moving.

3. What are the effects of dark matter on galaxies?

Dark matter plays a crucial role in the formation and evolution of galaxies. Its gravitational effects help to hold galaxies together and prevent them from flying apart due to their high speeds. Dark matter also helps to shape the structure of galaxies, influencing the distribution of stars and gas within them. Without dark matter, galaxies would look very different and may not even exist in their current form.

4. Is dark matter the same as dark energy?

No, dark matter and dark energy are two different things. Dark matter is a type of matter that has mass and exerts gravitational effects, while dark energy is a mysterious force that is thought to be causing the expansion of the universe to accelerate. Both dark matter and dark energy are currently not well understood, but they are thought to be separate phenomena.

5. Can we harness dark matter for energy or other practical purposes?

Unfortunately, we do not yet have the technology or understanding to harness dark matter for practical purposes. As its name suggests, dark matter is very difficult to detect and interact with, making it challenging to use for energy or other applications. However, studying dark matter and its effects on galaxies can lead to a better understanding of the universe and potentially open up new possibilities for future technologies.

Suggested for: Exploring the Nature of Dark Matter and Its Effects on Galaxies

Replies
9
Views
1K
Replies
15
Views
1K
Replies
1
Views
1K
Replies
13
Views
904
Replies
8
Views
2K
Replies
6
Views
1K
Replies
8
Views
1K
Back
Top