Everything we see when we look at the sky with the naked eye, or even with the most powerful telescopes, is made of the same fundamental constituents.Planets, stars and gas are in fact made of the same atoms that constitute the matter we are familiar with on Earth, including organic matter, and therefore ourselves.
However, a wide array of indirect observations provides compelling evidence for a new form of matter, known as Dark Matter, which is profoundly different from, and 5 times more abundant than, ordinary matter. The aim of my research program is to exploit the experimental results of the Large Hadron Collider at CERN, and of the upcoming generation of Astroparticle experiments, to identify the nature of Dark Matter particles.
For more details, click on the ‘Books’ link above, or read the review article
(Gianfranco Bertone, Dan Hooper and Joe Silk, Phys.Rept.405:279-390,2005)
Cosmic rays are particles whose existence is revealed by the observation of electromagnetic cascades, i.e. showers of secondary charged particles, originating in the upper atmosphere and reaching the Earth’s surface. Their energy spectrum covers about 11 orders of magnitude and extends up to extreme energies, above 10^20 eV.
Excellent introductions to this subject here.
(Image Credit: NSF/J. Yang)
Although we apparently live in 3+1 dimensions, it is in principle possible that other dimensions exist and that we are for some reasons limited in our ability to experience them.From the point of view of physics, extra-dimensions (ED) received great attention after the idea of Kaluza, in 1921, to unify electromagnetism with gravity by identifying the extra components of the metric tensor with the usual gauge fields.Today, additional motivation for the study of theories with ED is that string theory and M-theory, which are today the best candidates to a consistent theory of quantum gravity and a unified description of all the interactions, can be formulated in theories with six or seven extra-dimensions.We use astrophysical data to corroborate or constrain these theories.