A recap of what made news in the world of science and technology this week.

Astronomers find largest stellar black hole in Milky Way

Astronomers have identified the most massive stellar black hole yet discovered in our galaxy—in the Milky Way. On 16 April, the European Southern Observatory (ESO) said in a news release that this black hole was spotted in data from the European Space Agency’s Gaia mission. Stellar black holes, according to ESO, are formed from the collapse of massive stars. Researchers were able to spot the black hole—named Gaia BH3—because it imposes an odd “wobbling” motion on the companion star orbiting it. Data from the ESO’s Very Large Telescope and other ground-based observatories were used to verify the mass of the black hole. It is about 33 times greater than that of our sun and located about 2,000 light years from Earth. The findings were published earlier this week in the journal Astronomy and Astrophysics.

New X users may have to pay to like, post 

New users on social media platform X might soon have to pay to like, post, bookmark and reply. The company said on 15 April that the move aims to reduce spam and “create a better experience for everyone.” Users can, however, follow accounts and browse X for free. According to a thread on the X Daily News handle, the new policy was previously only active in New Zealand and the Philippines. New unverified users are now receiving a dialogue box which states that they can unlock the ability to post and engage by paying a small fee. Replying to the thread, X CEO Elon Musk said: “Unfortunately, a small fee for new user write access is the only way to curb the relentless onslaught of bots… Current AI (and troll farms) can pass ‘are you a bot’ with ease.” Musk added that the onslaught of fake accounts also uses up the available namespace, which results in many handle names being taken.

A new AI pendant makes its debut

While all the talk about wearable AI in recent months has centered around the Humane AI Pin, a new AI pendant is grabbing global attention as well. The Limitless Pendant, unveiled on 16 April, is a lightweight AI wearable that remembers what a user says throughout the day, from in-person meetings, impromptu conversations, and personal insights. According to its website, the Pendant has a 100-hour battery life and comes with Wi-Fi and Bluetooth features. Users can wear it using a versatile magnetic clasp. In an introductory video, CEO Dan Siroker also unveiled the Limitless AI web, Mac and Windows app, along with the wearable. Siroker said the Pendant has an array of microphones that can record crystal-clear audio in a crowded environment. The device, priced at $99 (around ₹8,280), will start shipping in Q4 this year.

—Compiled by Nitin Sreedhar.

Also read: Week in tech: Scientists unveil new secrets about Milky Way’s black hole