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Astronomers can estimate ages for stars outside the Solar System, but not planets. Corbis Historical via Getty Images

How do astronomers know the age of the planets and stars?

Measuring the ages of planets and stars is tricky. An observational astrophysicist describes the subtle clues that provide good estimates for how old different space objects are.
Sen. Bob Menendez and his wife arrive at the U.S. District Court in New York City on Sept. 27, 2023. Timothy A. Clary/AFP via Getty Images

Feinstein’s death raises the question: How are vacant Senate seats filled?

California’s governor has already announced his pick for the the seat, Laphonza Butler. Here’s more on the state-by-state process for replacing a senator who has died, is facing criminal charges or has serious illness.
The intersection of politics and social media is fertile ground for AI-powered disinformation. AP Photo/John Minchillo

AI disinformation is a threat to elections − learning to spot Russian, Chinese and Iranian meddling in other countries can help the US prepare for 2024

ChatGPT and its ilk give propagandists and intelligence agents a powerful new tool for interfering in politics. The clock is ticking on learning to spot this disinformation before the 2024 election.
Regular testing for HIV protects you and those around you. pixinoo/iStock via Getty Images Plus

HIV self-test kits are meant to empower those at risk − but they don’t necessarily lead to starting HIV treatment or prevention

Many people at heightened risk for HIV have never been tested. Those who have self-tested for HIV often don’t go on to receive care or change their sexual behavior.
The obligatory showing of the red briefcase containing budget details is as exciting as it gets in the U.K. Rob Welham/Universal History Archive/Universal Images Group via Getty Images

Shutdowns are a uniquely American drama − in the UK, it’s just not Parliament’s cup of tea

With the US government seemingly heading toward a potentially painful federal shutdown, a scholar explains why such events never occur in the UK.

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