Technologies

NASA’s Hubble telescope helps scientists solve mystery of dead galaxies

Why did some galaxies from the early universe suddenly stop making stars? Astronomers look back in time to find out.

As mere mortals, we yearn to travel back in time — an obsession nourished by iconic contraptions such as Marty McFly’s car, Hermione Granger’s time turner and Doctor Who’s police box. Often forgotten, however, are the real-life astronomers who kind of already do it.

Recently, one such research team tapped time travel to solve a space mystery from billions of years ago using a unique combination of super sensitive telescopes: Why did some of the early universe’s galaxies strangely stop popping out stars and become inactive, or quiescent?

Galaxies are thought to be at the pinnacle of their star manufacturing potential at this moment in time, so it’s especially puzzling when we discover any that are dormant. Right now, they should be making more stars than ever.

«The most massive galaxies in our universe formed incredibly early, just after the Big Bang happened,» Kate Whitaker, a professor of astronomy at University of Massachusetts-Amherst and lead author of a new study, said in a statement. «But for some reason, they have shut down. They’re no longer forming new stars.»

It turns out, some old galaxies merely ran low on star fuel, or cold gas, early on in their lifetimes. The results of the group’s study were published Wednesday in the journal Nature and could rewrite our knowledge of how the universe evolved.

But hold on, you’re probably still on that bit about astronomers going back in time. If they can swing that, why didn’t they show up to Stephen Hawking’s famous time-traveler-only dinner party?

You might have heard the term «light-year,» which refers to the distance light whizzes along in one Earth year. We need this term as a measurement because light doesn’t travel instantaneously. Of course, turning on your bedroom lamp leads to near-immediate brightness, but if someone turned on a flashlight while standing on the moon, about 238,900 miles (384,472 kilometers) away, its beam wouldn’t reach us for over a second.

That means moonlight has about a one-second lag for us Earthlings. In effect, when we glance at the moon, we’re seeing everything one second after it happens. We’re sort of looking back in time.

Astronomers scale that concept up by the billions. Using powerful telescopes as time machines, they look into deep space — like, billions of light-years away. For this study that mined the mystery of prematurely «dying» galaxies, for instance, the team looked at six cosmic bodies 10 billion to 12 billion light-years away in the universe.

So, it took 10 billion to 12 billion years for any illumination within the studied area to reach their telescope lenses. That means the astronomers were looking back in time far enough to watch the moments soon after the Big Bang — which occurred about 14 billion years ago — unfold in real-time.

Lo and behold, that’s how they solved the cosmic puzzle. The researchers say the galaxies either burned through their cold gas supply too quickly or are blocked from replenishment.

More specifically, Whitaker and fellow researchers demystified the issue by using a mixture of powerful telescopes: the Hubble Space Telescope and the Atacama Large Millimeter/submillimeter Array, or ALMA. The Hubble Space Telescope is sensitive to light across the spectrum — even the type humans can’t see.

And as if time travel wasn’t fantastical enough, the team took advantage of another tool called gravitational lensing to enhance the light collected. Basically, the lens’ viewpoint traveled along a line decorated by hundreds of other galaxy clusters.

Gravitational pulls of those galaxies were strong enough to warp beams of light coming from the team’s six galaxies of interest, stretching them while they traveled to Earth. That helped shed light — no pun intended — on juicy details that would have otherwise been missed within the galaxies.

ALMA, on the other hand, used those details to look for levels of the cold gas, or star fuel, needed by galaxies to make stellar bodies. «There was copious cold gas in the early universe, so these galaxies, from 12 billion years ago, should have plenty left in the fuel tank,» Whitaker said.

Now we know — thanks to the closest we’ve come to time travel — those tanks have been empty.

Technologies

Today’s NYT Mini Crossword Answers for Tuesday, Oct. 14

Here are the answers for The New York Times Mini Crossword for Oct. 14.

Looking for the most recent Mini Crossword answer? Click here for today’s Mini Crossword hints, as well as our daily answers and hints for The New York Times Wordle, Strands, Connections and Connections: Sports Edition puzzles.

Today’s Mini Crossword has an odd vertical shape, with an extra Across clue, and only four Down clues. The clues are not terribly difficult, but one or two could be tricky. Read on if you need the answers. And if you could use some hints and guidance for daily solving, check out our Mini Crossword tips.

If you’re looking for today’s Wordle, Connections, Connections: Sports Edition and Strands answers, you can visit CNET’s NYT puzzle hints page.

Read more: Tips and Tricks for Solving The New York Times Mini Crossword

Let’s get to those Mini Crossword clues and answers.

Mini across clues and answers

1A clue: Smokes, informally
Answer: CIGS

5A clue: «Don’t have ___, man!» (Bart Simpson catchphrase)
Answer: ACOW

6A clue: What the vehicle in «lane one» of this crossword is winning?
Answer: RACE

7A clue: Pitt of Hollywood
Answer: BRAD

8A clue: «Yeah, whatever»
Answer: SURE

9A clue: Rd. crossers
Answer: STS

Mini down clues and answers

1D clue: Things to «load» before a marathon
Answer: CARBS

2D clue: Mythical figure who inspired the idiom «fly too close to the sun»
Answer: ICARUS

3D clue: Zoomer around a small track
Answer: GOCART

4D clue: Neighbors of Norwegians
Answer: SWEDES

Technologies

Watch SpaceX’s Starship Flight Test 11

Technologies

New California Law Wants Companion Chatbots to Tell Kids to Take Breaks

Gov. Gavin Newsom signed the new requirements on AI companions into law on Monday.

AI companion chatbots will have to remind users in California that they’re not human under a new law signed Monday by Gov. Gavin Newsom.

The law, SB 243, also requires companion chatbot companies to maintain protocols for identifying and addressing cases in which users express suicidal ideation or self-harm. For users under 18, chatbots will have to provide a notification at least every three hours that reminds users to take a break and that the bot is not human.

It’s one of several bills Newsom has signed in recent weeks dealing with social media, artificial intelligence and other consumer technology issues. Another bill signed Monday, AB 56, requires warning labels on social media platforms, similar to those required for tobacco products. Last week, Newsom signed measures requiring internet browsers to make it easy for people to tell websites they don’t want them to sell their data and banning loud advertisements on streaming platforms.

AI companion chatbots have drawn particular scrutiny from lawmakers and regulators in recent months. The Federal Trade Commission launched an investigation into several companies in response to complaints by consumer groups and parents that the bots were harming children’s mental health. OpenAI introduced new parental controls and other guardrails in its popular ChatGPT platform after the company was sued by parents who allege ChatGPT contributed to their teen son’s suicide.

«We’ve seen some truly horrific and tragic examples of young people harmed by unregulated tech, and we won’t stand by while companies continue without necessary limits and accountability,» Newsom said in a statement.

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One AI companion developer, Replika, told CNET that it already has protocols to detect self-harm as required by the new law, and that it is working with regulators and others to comply with requirements and protect consumers.

«As one of the pioneers in AI companionship, we recognize our profound responsibility to lead on safety,» Replika’s Minju Song said in an emailed statement. Song said Replika uses content-filtering systems, community guidelines and safety systems that refer users to crisis resources when needed.

A Character.ai spokesperson said the company «welcomes working with regulators and lawmakers as they develop regulations and legislation for this emerging space, and will comply with laws, including SB 243.» OpenAI spokesperson Jamie Radice called the bill a «meaningful move forward» for AI safety. «By setting clear guardrails, California is helping shape a more responsible approach to AI development and deployment across the country,» Radice said in an email.

One bill Newsom has yet to sign, AB 1064, would go further by prohibiting developers from making companion chatbots available to children unless the AI companion is «not foreseeably capable of» encouraging harmful activities or engaging in sexually explicit interactions, among other things.