Year in Review
Mysterious particles called neutrinos constantly barrel down on Earth from space. No one has known where, exactly, the highest-energy neutrinos come from. This year, scientists finally put a finger on one likely source: a brilliant cosmic beacon called a blazar. The discovery could kick-start a new field of astronomy that combines information gleaned from neutrinos and light.
Voyager 2 has entered interstellar space. The spacecraft slipped out of the huge bubble of particles that encircles the solar system on November 5, becoming the second ever human-made craft to cross the heliosphere, or the boundary between the sun and the stars.
Coming in second place is no mean achievement. Voyager 1 became the first spacecraft to exit the solar system in 2012. But that...
For years, some physicists have rowed against the tide, controversially claiming that they’ve found the universe’s elusive dark matter, despite mounting evidence to the contrary. A new experiment makes that upstream paddling even more of a challenge.
Observations of the cosmos indicate that an invisible, unknown type of subatomic particle must pervade the universe. The extra mass this...
News in Brief
The world’s most powerful particle accelerator has gone quiet. Particles took their last spin around the Large Hadron Collider on December 3 before scientists shut the machine down for two years of upgrades.
Located at the particle physics laboratory CERN in Geneva, the accelerator has smashed together approximately 16 million billion protons since 2015, when it reached its current...
A proton’s mass is more than just the sum of its parts. And now scientists know just what accounts for the subatomic particle’s heft.
Protons are made up of even smaller particles called quarks, so you might expect that simply adding up the quarks’ masses should give you the proton’s mass. However, that sum is much too small to explain the proton’s bulk. And new, detailed calculations...