NASA’s leading planet-hunting spacecraft has spotted its second planet that matches Earth’s size and may be able to retain liquid water — and both worlds orbit the same star.

NASA’s Transiting Exoplanet Survey Satellite (TESS) launched in April 2018; since then, the mission has discovered 285 confirmed exoplanets and more than 6,000 candidates. One of the most intriguing of the confirmed planets is a world dubbed TOI 700 d, which is about the size of Earth and located in its star’s habitable zone. Now, scientists have determined that the planet has a neighbor that’s just as tantalizing, thanks to an October 2021 alert that the Earth-orbiting telescope had seen something interesting.

It’s been well over 100 years since Einstein presented his theory of General Relativity, and physicists have been continually testing it against every piece of evidence they can get their hands on. In a series of three papers, researchers looked at data from the 4th run of the LIGO/Virgo/KAGRA detections of black hole mergers, to see if General Relativity is consistent with the data. As you might expect, Einstein’s predictions hold, without the need for an alternative model to fix them.

• Earth’s day length varies by several milliseconds over decades, and a new model suggests the dominant driver is a gravitational tug between the slightly misshapen solid inner core and density variations in the mantle.
• Changes in inner-core rotation shift it away from gravitational alignment with the mantle, producing torque that speeds or slows the mantle, while electromagnetic or topographic forces at the core-mantle boundary resist that motion.

• Supermassive black holes appear to launch delayed radio jets when their feeding rate falls to about 2% of the Eddington limit, matching a threshold already measured around stellar-mass black holes.
• The team reconstructed 11 radio outflows from 10 well-observed tidal disruption events, revealing separate high-accretion and low-accretion phases associated with different kinds of outflows.
• The result supports the idea that black hole feeding and jet formation obey the same underlying physics across a mass range spanning roughly seven orders of magnitude.

• GJ 3090 b, a sub-Neptune about 2.18 times Earth’s radius, follows a strongly misaligned retrograde orbit around its small red dwarf host star.
• Astronomers measured a three-dimensional spin-orbit angle of about 136 degrees, making GJ 3090 b the first known retrograde planet around an M dwarf.

Of the over 6,000 exoplanets astronomers have discovered so far, we’ve seen a huge range of ages. Some have been far older than Earth, and others mere planetary babies. But none have been nearly as young as the newly spotted planet Elias 2-24 b.

This world is less than a million years old. It’s still shrouded in the disk of gas and dust that surrounds its star, meaning it can still pull in material to keep growing.

ESA has just released one of the largest James Webb Space Telescope images yet, and it’s spectacular

The image reveals a nearby cloud of gas and dust known as IC 348. Sitting about 1,000 light-years away in the constellation Perseus the Hero, IC 348 is a star-formation hotbed.

• Gaia measurements of 7,426 massive stars in the Small Magellanic Cloud reveal opposing motions across the galaxy, with eastern regions generally moving southeast toward the Large Magellanic Cloud while western regions move northwest.
• The pattern does not resemble ordinary galactic rotation and instead supports the idea that tidal forces, possibly combined with ram pressure, are stretching and disrupting the smaller galaxy.

The early days of solar system formation were chaotic! Planetesimals – ranging from a few hundred meters to hundreds of kilometers across – smashed into each other and clumped together to form planets, or flew apart.  A planet-sized body apparently hit Earth to become our moon.  And some of those early, turbulent motions likely involved material spiraling into our sun as well.

• Einstein’s theory of gravity may behave slightly differently across distances of billions of light-years, with gravity appearing about 1 percent weaker on cosmic scales.
•                   The proposed “cosmic glitch” modestly improves some cosmological measurements and eases the disagreement over how fast the universe is expanding, although it does not resolve the problem.
• Current evidence remains tentative, and future observations from projects such as DESI and Euclid could reveal whether the effect is real or disappears with better data.