Fresh observations of Comet 46P/Wirtanen, which swung by Earth in December 2018, suggest that more of Earth's water came from comets than previous studies suggested.
Comets are remnants from the early days of the solar system, billions of years ago. Primarily made of ice and dust, these "dirty snowballs" orbit the sun and in habit the Oort cloud, an area in the outskirts of the solar system beyond Pluto. As comets approach the inner solar system, solar wind from the sun can sweep dust back into a long tail. When these comets are close enough to Earth, they can appear as dazzling objects in the night sky. Space probes from Earth have visited several comets to learn more about their composition. Learn more about comets, icy wanderers in the solar system.
Recently, a friend of mine asked when we might be able to see a comet. He was surprised when I said there are several visible right now.
Can you spot a cat in this cosmic image? This photo — just one of 70,000 available in a new Rosetta spacecraft image archive — has a cometary view that looks like a cat's face from side-on.
Researchers have found a piece of a comet — an object made up of ice and dust — inside of a space rock known as a stony meteorite.
A quarter century ago and thousands of miles away, a dramatic weeklong cosmic collision unfolded and helped the internet gain a foothold in people's lives.
In this deep-space photo, the bright-green Comet 21P/Giacobini-Zinner blazes across a sparkling star field, passing by the open star cluster M37 as it makes its way through the Auriga constellation.
The brilliant, blue-green comet C/2018 Y1 Iwamoto will zip by Earth this week, and the speedy space "snowball" is currently visible in the night sky with binoculars and small telescopes.
'Oumuamua is long gone, but it's still leaving scientists guessing. A new explanation proposes that the strange object was a "monstrous fluffy dust aggregate" produced by a busted-up comet.
The dense atmosphere roiling on Saturn's largest moon, Titan, may come from organic material baking in the moon's interior.
Names matter, even when they're temporary nicknames for objects 4.1 billion miles (6.6 billion kilometers) away from Earth.
Just in time for Christmas, the latest apparition of a comet shines like a beautiful ornament in the sky — a delightful green-shrouded treat for amateurs and scientists alike.
You can expect a ghostly green blob to grow brighter in the sky near Orion in the coming days, as Comet 46P/Wirtanen makes its closest approach to the Earth in 20 years this weekend.
The Geminid meteor shower will provide a shining backdrop for the approach of Comet 46P/Wirtanen on Thursday (Dec. 13), shortly before the object's closest approach to Earth in 20 years.
See skywatcher photos of the bright-green, naked-eye Comet 46P/Wirtanen during its close approach to Earth in December 2018.
As you read this, a small comet is on its way toward making a very close pass of Earth in mid-December — its best appearance over a period of four centuries.
Scientists are one step closer to understanding why some comets have strange dust bands in their tails. The main culprit in this cosmic mystery? Our own sun.