Weird and mysterious radio signals coming from outer space often are followed by claims of "aliens did it." That's likely not the case, says one astrophysicist.
Imagine Tycho Brahe's surprise when he examined in detail a new star that appeared in the November sky of 1572 — a nova.
It's only in the habitable zone — the "Goldilocks" region around a star where water can exist in liquidy peace — that life is possible. Or so scientists thought.
Instead of just sitting back, relaxing and enjoying the light show the universe is putting on, some people feel compelled to object: Those colors are fake! Here's why such complaints are unwarranted.
It's not often that you can get promoted, commended and even awarded for failing to do your job. But that's just what happened to the discoverers of the key evidence supporting the Big Bang theory.
Something in the deep reaches of space is pulling Earth's galactic neighborhood toward it. What is this so-called Great Attractor, and will it eventually swallow up our cosmic home?
If our only satellite vanished in the blink of an eye, would you notice? Does it even matter? Astrophysicist Paul Sutter explains.
The universe is expanding, but what's it expanding into? Nothing! Astrophysicist Paul Sutter explains this baffling concept, plus how the universe can expand but not have an edge.
Without an infinitely long ruler, how can you measure the distances to the universe's farthest galaxies?
Studying the ripples in space-time known as gravitational waves could allow astronomers to open a new window on the universe.