Month: July 2024

Enlarge / Renditions of a possible composition of LHS 1140 b, with a patch of ocean on the side facing its host star. Earth is included at right for scale. (credit: BENOIT GOUGEON, UNIVERSITÉ DE MONTRÉAL)

Of all the potential super-Earths—terrestrial exoplanets more massive than Earth—out there, an exoplanet orbiting a star only 40 light-years away from us in the constellation Cetus might be the most similar to have been found so far.

Exoplanet LHS 1140 b was assumed to be a mini-Neptune when it was first discovered by NASA’s James Webb Space Telescope toward the end of 2023. After analyzing data from those observations, a team of researchers, led by astronomer Charles Cadieux, of Université de Montréal, suggest that LHS 1140 b is more likely to be a super-Earth.

If this planet is an alternate version of our own, its relative proximity to its cool red dwarf star means it would most likely be a gargantuan snowball or a mostly frozen body with a substellar (region closest to its star) ocean that makes it look like a cosmic eyeball. It is now thought to be the exoplanet with the best chance for liquid water on its surface, and so might even be habitable.

Enlarge / This artist's concept shows the possible appearance of ESA's RAMSES spacecraft, which will release two small CubeSats for additional observations at Apophis. (credit: https://www.esa.int/Space_Safety/Planetary_Defence/Introducing_Ramses_ESA_s_mission_to_asteroid_Apophis)

For nearly 20 years, scientists have known an asteroid named Apophis will pass unusually close to Earth on Friday, April 13, 2029. But most officials at the world's space agencies stopped paying much attention when updated measurements ruled out the chance Apophis will impact Earth anytime soon.

Now, Apophis is again on the agenda, but this time as a science opportunity, not as a threat. The problem is there's not much time to design, build and launch a spacecraft to get into position near Apophis in less than five years. The good news is there are designs, and in some cases, existing spacecraft, that governments can repurpose for missions to Apophis, a rocky asteroid about the size of three football fields.

Scientists discovered Apophis in 2004, and the first measurements of its orbit indicated there was a small chance it could strike Earth in 2029 or in 2036. Using more detailed radar observations of Apophis, scientists in 2021 ruled out any danger to Earth for at least the next 100 years.