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Astronomers Prove To Einstein That Stars Can Warp Light (theverge.com)
Astronomers have observed for the first time ever a distant star warp the light of another star, "making it seem as though the object changed its position in the sky," reports The Verge. The discovery is especially noteworthy as Albert Einstein didn't think such an observation would be possible. From the report: These events require stars that are very far apart to line up perfectly. That's why Einstein once wrote that "there is no hope of observing this phenomenon directly." Our telescope technology has become far more sophisticated than in Einstein's day -- which is what allowed us to observe something he thought we'd never see. In 2014, a group of astronomers using NASA's Hubble Space Telescope spotted a rare type of microlensing, when a dense white dwarf star passed in front of another star thousands of light-years away. The stars weren't exactly aligned, but they were close enough that the white dwarf made it seem like the background star performed a small loop in the sky. "It looks like the white dwarf pushed it out of the way," Terry Oswalt, an astronomer at Embry-Riddle Aeronautical University who was not involved in this discovery but wrote a perspective piece in Science, tells The Verge. "That's not what happened, of course. It just looks like that." The astronomers also used the apparent movement of the background star to measure the mass of the passing white dwarf, a novel technique detailed in a paper published today in Science. And they say this isn't the last time they'll make measurements like this either. Now that they've figured out how to spot these kinds of lensing events, they're hoping to find even more with new ground- and space-based telescopes that are coming online soon.
Very good question, because of the quite bad headline.
At the time of writing his original paper regarding light bending between two stars, Einstein was already sure that the light-bending effect occurs (it had been already observed during a solar eclipse in 1919). However, he assumed that it would never be observable with two stars, one in the background and other in the foreground (different to the sun) because the light of the two stars would merge and not be distinguishable. From his paper (full copy here): Of course, there is no hope of observing this phenomenon directly. First, we shall scarcely ever approach closely enough to such a central line. Second, the angle b will defy the resolving power of our instruments [...]".
The relevant contribution is that current science (Hubble resolution) and appropriate search has managed to observe this effect. In particular, the linked overview clarifies it: Because the foreground star observed by Sahu et al. was about 400 times brighter than the background star, the brightening of their combined light was far too small to be detectable even with Hubble. However, the apparent displacement in the background star’s position, so-called “astrometric lensing,” was measurable. The interesting part is that by measuring the displacement of light, they have been also able to measure the mass of the star, and determine that it is not an exotic "iron core" white dwarf.
The fact that they still use Einstein's name in clickbait headlines is tribute to his genius.
When he said "there is no hope of observing this phenomenon directly" he probably meant "there is no hope of us observing this phenomenon directly", not "there is no hope of ever observing this phenomenon directly"
People observed the sun bending light in 1919 - well inside Einstein's lifetime.
https://en.wikipedia.org/wiki/...
No sig today...
The headline is worse than that. It implies that Einstein didn't believe in the existence of the phenomenon in question...
Oh it's even worse because the reason Einstein (and everyone else) believed his theory of general relativity was correct was due to the Arthur Eddington's expedition to view the solar eclipse of 1919 where he observed that the sun bent the light of a distant star changing its apparent position!
What is even more insane is that both the articles linked in the summary start out mentioning this 1919 observation proving that the submitter either never read the articles he was submitting or did not understand what they were talking about. This article is clearly a contender for the most ignorant article on slashdot award.