Academic Awards

Subrahmanyan Chandrasekhar famously stated that black holes are “the most perfect macroscopic objects there are in the Universe: The only elements in their construction are our concepts of space and time.” His observation relates to the fact that astrophysical black holes, as described by the Kerr spacetime, can be characterized by just two parameters: mass and spin. However, things might get more complex. Theorists have predicted that if a bosonic field interacts with a Kerr black hole, perturbations in the field can grow to form a cloud around the black hole, creating a “gravitational atom,” in which the bosons surrounding the black hole behave somewhat like the electrons surrounding an atomic nucleus . What’s more, if such a gravitational atom is part of a binary involving a second black hole, excitations and ionization processes akin to those occurring in hydrogen atoms may affect how the black hole binary evolves. Giovanni Tomaselli of the University of Amsterdam and collaborators...

  New research hints at a fascinating and completely unexpected connection between Mars’s gravitational field and Earth’s climate. Geological evidence spanning over 65 million years suggests that deep-sea currents on Earth undergo recurring cycles of strength every 2.4 million years. These cycles, referred to as “astronomical grand cycles,” appear linked to gravitational interactions between Earth and Mars. Mars’s gravitational pull on Earth Mars and Earth tug on each other with their gravity as they move through space, creating small but noticeable effects called gravitational perturbations. Even though the planets are usually tens of millions of miles apart, their gravitational pull is strong enough to cause slight tweaks to each other’s orbits. During opposition, when Mars and Earth come closest – roughly every 26 months – Mars’s gravity nudges Earth’s orbit just a little. These changes are tiny and don’t disrupt Earth’s path in any major way, but over long periods, they can add...