Dark Matter Detection: Earth's Orbit and Its Interactions with the Solar System

In summary, the conversation discusses the discovery of dark matter particles and the controversy surrounding it. The DAMA collaboration has detected an annual modulation signal, but their methods have been criticized and their results have been disputed by other experiments. There is also skepticism about the credibility of the DAMA group as they have not made their raw data public. Despite this, it is acknowledged that they have found "something" and further research is needed to determine the true nature of this phenomenon.
  • #1
SF
The whole solar system is orbiting the center of the Milky Way at about 250 kilometers per second. But the Earth is also orbiting the Sun. When the Earth is at one part of its orbit, its velocity (30 kps) adds to that of the solar system, but six months later it’s headed the other way, and its velocity subtracts.

If the Earth is slamming into dark matter particles, then we should hit more when the Earth and solar system velocities are in the same direction, and hit fewer when the Earth is moving in the opposite direction of the solar system as a whole six months later. So not only should we see the number of hits go up and down every six months, but that oscillation must line up with the correct dates (June for the former, and December for the latter).

http://www.badastronomy.com/bablog/2008/04/21/dark-matter-detected/
 
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  • #2
SF said:
The whole solar system is orbiting the center of the Milky Way at about 250 kilometers per second. But the Earth is also orbiting the Sun. When the Earth is at one part of its orbit, its velocity (30 kps) adds to that of the solar system, but six months later it’s headed the other way, and its velocity subtracts.

If the Earth is slamming into dark matter particles, then we should hit more when the Earth and solar system velocities are in the same direction, and hit fewer when the Earth is moving in the opposite direction of the solar system as a whole six months later. So not only should we see the number of hits go up and down every six months, but that oscillation must line up with the correct dates (June for the former, and December for the latter).

http://www.badastronomy.com/bablog/2008/04/21/dark-matter-detected/

What you are talking about is the DAMA collaboration which has now reconfirmed its own results from a couple of years ago. If I have understood the situation right, they have basically used the same method as in their first experiment, which is unfortunate since this makes it hard to rule out a possible non-dark matter explanation of the anually modulated signal.

Note that, at least for standard dark matter particle models, the DAMA claim has already been ruled out by many other types of direct detection experiments. Hence their results have been greatly disputed in the past, and I'm not sure this experiment will help that much.

A big problem for DAMA is their credibility: They constantly refuse to make their raw data public and by that makes it as good as impossible for others to debug their analysis.
 
  • #3
EL said:
What you are talking about is the DAMA collaboration which has now reconfirmed its own results from a couple of years ago. If I have understood the situation right, they have basically used the same method as in their first experiment, which is unfortunate since this makes it hard to rule out a possible non-dark matter explanation of the anually modulated signal.

Note that, at least for standard dark matter particle models, the DAMA claim has already been ruled out by many other types of direct detection experiments. Hence their results have been greatly disputed in the past, and I'm not sure this experiment will help that much.

A big problem for DAMA is their credibility: They constantly refuse to make their raw data public and by that makes it as good as impossible for others to debug their analysis.

Well at any rate, it does sound like they found SOMETHING. Even if people rule out dark matter, I'd be curious to see what it is that they've found.
 
  • #4
There's a great opinion piece from someone in the field of DM detection, but not in the DAMA group, over at http://cosmicvariance.com/2008/04/21/guest-post-juan-collar-on-dark-matter-detection/" .
 
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  • #5
Nabeshin said:
Well at any rate, it does sound like they found SOMETHING. Even if people rule out dark matter, I'd be curious to see what it is that they've found.
I don't think anyone doubted they had really found "something" in their first experiment either. The problem is that this "something" could be "anything". It's not hard to think of possible background components with annual modulation.
I think Wallaces link summarizes the scepticism from the dark matter community pretty well.
 

1. What is dark matter and why is it important to study?

Dark matter is a hypothetical type of matter that is thought to make up about 85% of the total matter in the universe. It does not interact with light, making it invisible and difficult to detect. Studying dark matter is important because it plays a crucial role in the formation and evolution of galaxies and the large-scale structure of the universe.

2. How do scientists detect dark matter in Earth's orbit?

Scientists use a variety of methods to detect dark matter in Earth's orbit, including direct detection experiments using detectors located deep underground, and indirect detection experiments that look for particles or radiation produced by dark matter interactions. These experiments aim to detect the energy or momentum that dark matter particles would transfer to normal matter particles upon interaction.

3. How does dark matter interact with the solar system?

Dark matter is thought to interact with the solar system through its gravitational pull. It is believed to have played a role in the formation and evolution of the solar system, as well as influencing the motion of planets and other objects within the system.

4. What are some current theories about the nature of dark matter?

There are several theories about the nature of dark matter, including the possibility that it is made up of a new type of particle that has not yet been detected, or that it is made up of a large number of small primordial black holes. Other theories suggest that dark matter may be a manifestation of an extended gravity theory, or that it is not a matter at all, but a modification of the laws of gravity.

5. How does studying Earth's orbit and its interactions with the solar system help in the search for dark matter?

Studying Earth's orbit and its interactions with the solar system can provide valuable information about the distribution and properties of dark matter in our galaxy. By measuring the gravitational effects of dark matter on the orbits of planets and other objects in the solar system, scientists can gain insights into the nature of this mysterious substance and potentially narrow down the search for its true identity.

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