There was big news in astrophysics this week: An experiment detected ripples in space-time, known as gravitational waves, created by two black holes colliding in space 1.4 billion light-years from Earth. That certainly sounds … complicated. But what's the big deal, exactly? Why are scientists so excited about this new discovery? What does it tell them about the universe? Let's break it down. [Hunting Gravitational Waves: The LIGO Laser Interferometer Project in Photos] What's so cool about gravitational waves? The first significant thing about LIGO's direct detection of gravitational waves is that it happened at all. But first, let's back up a bit and talk about Albert Einstein. He was a smart
Astrophysicist Adam Riess shared the 2011 Nobel Prize in physics for research showing that the universe isn’t simply expanding (something we’ve known since Edwin Hubble's landmark 1929 paper) but that it's expanding at an accelerating rate. Now Riess, along with an international team of collaborators, is back with surprising new research showing that the universe is expanding faster than predicted. Or, if you prefer your astronomy in simple terms: The universe is expanding about 9 percent faster than we thought. “I know this might not sound all that fast to most folks, but that is about 800 million years faster than we previously thought,” Riess, a 46-year-old professor at Johns Hopkins University, told The Huffington Post in an email.
A single star is a wonder. A million stars is a story. A star can burn for billions, even trillions of years. With human history spanning mere centuries, how can we possibly understand the lifespan of a star? If we only had the Sun to study, understanding it’s history would be difficult, but we can observe millions of stars, some ancient and some still forming. By looking at these stars as a whole we can piece together the history and evolution of a star. It is similar to taking pictures of a single day on Earth, and using it to piece together the story of how humans are born, live and die. One of the ways this is done is through a Hertzsprung-Russell (HR) diagram. The brightness of a star is
About 4.5 billion years ago, scientists estimate that Earth collided with an object the size of Mars. The collision vastly reduce the size of early Earth, and from the aftermath and debris, our Moon formed. Video courtesy of NASA