SCIENCE
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Ask Ethan: Why do gravitational lenses make crosses, not rings?
Gravitational lenses arise when foreground masses and background light sources properly align. Einstein rings are rare, but crosses abound. Continue…
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It’s time to stop teaching the biggest lie about Hawking radiation
It’s not about particle-antiparticle pairs falling into or escaping from a black hole. A deeper explanation alters our view of…
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NASA watched this supernova blast expand for 25 years
Back in 1604, Johannes Kepler discovered the Milky Way’s last naked-eye supernova. Here’s how NASA’s Chandra sees it over the…
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Ask Ethan: What does “gravitationally bound” mean in the expanding Universe?
When objects are gravitationally bound, they cannot escape from one another’s influence. How does that work within the expanding Universe?…
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Astronomers are on “Cloud 9” with a new, starless gas cloud
Astronomers have found starless gas clouds before, but Cloud 9 might be the most pristine one of all, with big…
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Ask Ethan: Why is there no such thing as antigravity?
In general relativity, matter and energy curve spacetime, which we experience as gravity. Why can’t there be an “antigravity” force?…
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Why scientists can’t stop searching for alien life
There will always be “wolf-criers” whose claims wither under scrutiny. But aliens are certainly out there, if science dares to…
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Does our physical reality exist in an objective manner?
We think of physical reality as what objectively exists, independent of any observer. But relativity and quantum physics say otherwise.…
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How recently have we understood the Universe?
While humanity has been skywatching since ancient times, much of our cosmic understanding has come about only recently. Very recently.…
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Ask Ethan: Can stars form within the expanding Universe?
Our Universe doesn’t just expand and cool, but the expansion itself is accelerating. Can stars form under such structure-erasing… Continue…
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