Lifeboat Foundation

The interiors of giant planets remain poorly understood. Even for the planets in the Solar System, difficulties in observation lead to large uncertainties in the properties of planetary cores. Exoplanets that have undergone rare evolutionary processes provide a route to understanding planetary interiors. Planets found in and near the typically barren hot-Neptune ‘desert’^1,2 (a region in mass–radius space that contains few planets) have proved to be particularly valuable in this regard. These planets include HD149026b³, which is thought to have an unusually massive core, and recent discoveries such as LTT9779b⁴ and NGTS-4b⁵, on which photoevaporation has removed a substantial part of their outer atmospheres. Here we report observations of the planet TOI-849b, which has a radius smaller than Neptune’s but an anomalously large mass of \(39.1{\,}_{-2.6}^{+2.7}\) Earth masses and a density of \(5.2{\,}_{-0.8}^{+0.7}\) grams per cubic centimetre, similar to Earth’s. Interior-structure models suggest that any gaseous envelope of pure hydrogen and helium consists of no more than \({3.9}_{-0.9}^{+0.8}\) per cent of the total planetary mass. The planet could have been a gas giant before undergoing extreme mass loss via thermal self-disruption or giant planet collisions, or it could have avoided substantial gas accretion, perhaps through gap opening or late formation⁶. Although photoevaporation rates cannot account for the mass loss required to reduce a Jupiter-like gas giant, they can remove a small (a few Earth masses) hydrogen and helium envelope on timescales of several billion years, implying that any remaining atmosphere on TOI-849b is likely to be enriched by water or other volatiles from the planetary interior. We conclude that TOI-849b is the remnant core of a giant planet.

Astronaut Christina Koch spent a record 11 months in space, the longest spaceflight of any woman. She returned to Earth in February and is just completing her NASA-mandated readjustment period. What’s life like when you leave a space station, only to be confined in your own home under lockdown?

Guests

Christina Koch, NASA astronaut and former flight engineer on the International Space Station. She set the record for longest single spaceflight by a woman: 328 days. She and Jessica Meir performed the first all-female spacewalk. Koch has performed a total of six spacewalks. (@Astro_Christina)

NASA astronauts on the International Space Station are celebrating Independence Day from space.

Accelerating Change is a series by @amandngocnguyen profiling the world’s top change makers

“Houston, we have a problem.”

Astronaut Leland Melvin was training to perform a spacewalk at NASA’s Neutral Buoyancy Laboratory, a five million gallon pool that simulates space’s micro gravity, when he realized something had gone wrong. Very wrong.

Astronomers have discovered the surviving core of a gas giant, orbiting a distant star. The discovery provides a unique opportunity to analyse the interior of a planet first-hand.

NASA has released a stunning 61-minute time-lapse video that shows a decade in the life of the sun.

The video was created from images taken by NASA’s Solar Dynamics Observatory.

Continue reading “Stunning NASA time-lapse video shows 10 years in life of sun” »

The Hubble Space Telescope has been enhancing our understanding of the universe through breathtaking images for 30 years — PBS Digital Studios celebrates Hubble’s 30th anniversary.

Korolev crater on Mars—the largest ice skating rink in the solar system, basically—has never looked more enthralling than it does in this impressive new visualization.

The SLS is finally starting take shape.