‘Echo mapping’ in faraway galaxies could measure vast cosmic distances

'Echo mapping' in faraway galaxies could measure vast cosmic distances
A disk of hot material around a supermassive black hole emits a burst of visible light, which travels out to a ring of dust that subsequently emits infrared light. The blue arrows show the light from the disk moving toward the dust and the light from both events traveling toward an observer. Credit: NASA/JPL-Caltech

When you look up at the night sky, how do you know whether the specks of light that you see are bright and far away, or relatively faint and close by? One way to find out is to compare how much light the object actually emits with how bright it appears. The difference between its true luminosity and its apparent brightness reveals an object’s distance from the observer.


Measuring the luminosity of a celestial object is challenging, especially with black holes, which don’t emit light. But the supermassive black holes that lie at the center of

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Amazon appeals product liability ruling to CA Supreme Court, citing ‘potentially vast blast radius’

Amazon argues that it shouldn’t be held liable for defects in products sold by others on its third-party marketplace, even when it holds and ships them from fulfilment centers such as this one. (GeekWire File Photo)

Amazon is asking the California Supreme Court to review an appeals court ruling in a landmark product liability case, seeking to avoid a precedent that would leave the tech giant open to legal claims over defective products sold by third parties through its online marketplace.

The company’s petition for review, filed Tuesday, argues that the appeals court took an “unprecedented leap” when it found that Amazon was not shielded from liability for a replacement laptop battery that allegedly exploded several months after purchase, causing severe injuries to the plaintiff in the suit, Angela Bolger.

“This Court has never extended strict liability to an entity that provides a forum or service used by others to

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