All posts tagged: space weathering

JWST finds a dark, airless exoplanet covered in rock like Mercury

JWST finds a dark, airless exoplanet covered in rock like Mercury

Published by Jenni Sidey

The light from LHS 3844 b does not suggest oceans, clouds, or even air. What it points to instead is a dark, battered surface. This surface may have more in common with Mercury or the Moon than with anything you would recognize from Earth. Using the Mid-Infrared Instrument, or MIRI, aboard the James Webb Space Telescope, a team led by Sebastian Zieba and Laura Kreidberg, from the Max Planck Institute for Astronomy and Center for Astrophysics | Harvard & Smithsonian, examined the rocky exoplanet’s dayside glow and used it to probe the planet’s surface. Their results, published in Nature Astronomy, suggest that LHS 3844 b is likely airless. They also found that it is coated either in fresh volcanic rock or in older material that has been darkened and ground down by space weathering over time. That alone marks a shift in what astronomers can do. For years, much of exoplanet science focused on atmospheres. Here, the target was rock. LHS 3844 b sits about 48.5 light-years away and is about 30 percent larger than …

‘God of chaos’ asteroid Apophis will pass very close to Earth in 2029

‘God of chaos’ asteroid Apophis will pass very close to Earth in 2029

Published by Jenni Sidey

For a brief stretch on April 13, 2029, a giant space rock will slip closer to Earth than some of the satellites parked high above the planet. That object is Apophis, an asteroid once treated as a serious threat. Now it is viewed as one of the most unusual scientific opportunities in modern astronomy. Apophis is not headed for impact. That part is settled. But the asteroid’s close flyby is still extraordinary because of what Earth itself may do to it on the way past. The asteroid, officially known as 99942 Apophis, is expected to pass about 20,000 miles, or 32,000 kilometers, above Earth’s surface. At roughly 375 meters across on average, it is large enough to command attention and close enough to become visible to the naked eye in parts of Europe, Africa, and Asia, weather permitting. In fact, space agencies say it will be the closest approach of an asteroid this size that scientists have known about in advance. That makes the 2029 event more than a sky show. It turns Earth into …