How exoplanets may hold the key to finding dark matter
0:00 – Intro & sponsor 1:20 – Evidence for Dark Matter 2:25 – Detecting dark matter 3:10 – Paper by Leane & Smirnov 3:37 – What are exoplanets? 3:48 – Dark matter behavior in Exoplanets 5:22 – Smoking gun 5:52 – Why not use neutron stars 6:43 – Super-Jupiters 7:02 – How do we detect exoplanet heat?
Dark Matter may be detected via Exoplanets. All the matter that is visible to us constitutes only about 18% of the total matter that we think actually exists in the universe. We know this because when all the known mass of a galaxy like the Milky Way is taken into account, the outermost stars of the galaxies are moving way too fast given the gravitational attraction that can calculated. The total gravity would be too weak to keep these stars bound within the galaxy.
When you calculate what the gravity of the galaxy would need to be in order to observe the rotational speeds that we observe, you can calculate the mass that should be there, but isn’t visible.
Since we can’t see it, and we don’t know what it is, we call it « dark » matter. It does not emit any light, nor interacts with ordinary things in any way that we can detect, except through gravity.
Scientists have tried detecting it in liquid Xenon baths, via sensors on silicon chips, and the Large Hadron Collider in Geneva. but so far to no avail. But in a new paper published in the journal physical review letters, Physicists Rebecca Leane and Juri Smirnov have proposed a clever way to detect them – heat from exoplanets.
According to their calculations, certain kinds of dark matter could drastically increase the temperatures of exoplanets near the center of our galaxy. Over time, a lot of dark matter particles can become captured especially by very massive exoplanets. At high concentrations, these particles can collide and annihilate each other. This would release energy in the form of heat. As this heat is absorbed by the planet, the temperature of the planet should increase. The larger the exoplanet and higher this effect should be.
Temperatures of some of these planets could be in the ballpark of 1,000 Kelvin. This is compared to a prediction of only 200 Kelvin for planets without this source of energy from dark matter. Planets in our solar system are probably too small to capture enough dark matter to make any difference it temperature.
Generally, the bigger the planet is, the better candidate it is for this kind of heat detection. Relatively small planets like Earth or Venus are too small to accumulate huge quantities of dark matter. So the ideal candidate would be planets larger than Jupiter called super Jupiters which can be 10 times bigger. These would potentially have a lot more dark matter accumulating in them and so should display higher temperatures than expected.