Posts Tagged ‘Space and Time’

By Rafi Letzter

Giant molecules can be in two places at once, thanks to quantum physics.

That’s something that scientists have long known is theoretically true based on a few facts: Every particle or group of particles in the universe is also a wave — even large particles, even bacteria, even human beings, even planets and stars. And waves occupy multiple places in space at once. So any chunk of matter can also occupy two places at once. Physicists call this phenomenon “quantum superposition,” and for decades, they have demonstrated it using small particles.

But in recent years, physicists have scaled up their experiments, demonstrating quantum superposition using larger and larger particles. Now, in a paper published Sept. 23 in the journal Nature Physics, an international team of researchers has caused molecule made up of up to 2,000 atoms to occupy two places at the same time.

To pull it off, the researchers built a complicated, modernized version of a series of famous old experiments that first demonstrated quantum superposition.

Researchers had long known that light, fired through a sheet with two slits in it, would create an interference pattern, or a series of light and dark fringes, on the wall behind the sheet. But light was understood as a massless wave, not something made of particles, so this wasn’t surprising. However, in a series of famous experiments in the 1920s, physicists showed that electrons fired through thin films or crystals would behave in a similar way, forming patterns like light does on the wall behind the diffracting material.

If electrons were simply particles, and so could occupy only one point in space at a time, they would form two strips, roughly the shape of the slits, on the wall behind the film or crystal. But instead, the electrons hit that wall in complex patterns suggesting the electrons had interfered with themselves . That is a telltale sign of a wave; in some spots, the peaks of the waves coincide, creating brighter regions, while in other spots, the peaks coincide with troughs, so the two cancel each other out and create a dark region. Because physicists already knew that electrons had mass and were definitely particles, the experiment showed that matter acts both as individual particles and as waves.

But it’s one thing to create an interference pattern with electrons. Doing it with giant molecules is a lot trickier. Bigger molecules have less-easily detected waves, because more massive objects have shorter wavelengths that can lead to barely-perceptible interference patterns. And these 2,000-atom particles have wavelengths smaller than the diameter of a single hydrogen atom, so their interference pattern is much less dramatic.

To pull off the double-slit experiment for big things, the researchers built a machine that could fire a beam of molecules (hulking things called “oligo-tetraphenylporphyrins enriched with fluoroalkylsulfanyl chains,” some more than 25,000 times the mass of a simple hydrogen atom) through a series of grates and sheets bearing multiple slits. The beam was about 6.5 feet (2 meters) long. That’s big enough that the researchers had to account for factors like gravity and the rotation of the Earth in designing the beam emitter, the scientists wrote in the paper. They also kept the molecules fairly warm for a quantum physics experiment, so they had to account for heat jostling the particles.

But still, when the researchers switched the machine on, the detectors at the far end of the beam revealed an interference pattern. The molecules were occupying multiple points in space at once.

It’s an exciting result, the researchers wrote, proving quantum interference at larger scales than had ever before been detected.

“The next generation of matter-wave experiments will push the mass by an order of magnitude,” the authors wrote.

https://www.space.com/2000-atoms-in-two-places-at-once.html?utm_source=notification

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BY LI YEN, EPOCH TIMES

France Córdova, National Science Foundation director, said in a statement: “Black holes have sparked imaginations for decades. They have exotic properties and are mysterious to us.”

In fact, the mysterious black holes, dubbed as “monsters” by scientists, are not empty space, according to NASA. They are instead, as presented in Albert Einstein’s theory of general relativity, made up of “a great amount of matter packed into a very small area,” mostly formed from “the remnants of a large star that dies in a supernova explosion.”

Einstein predicted the existence of massive and dense black holes in the universe, where the gravitational fields are so strong that even light can’t escape.

The German-born American physicist, widely regarded as a genius today, made known this theory to the world more than a century ago on Nov. 25, 1915, at the Prussian Academy of Sciences.

“About a hundred years ago, Albert Einstein gave us a new description of the force of gravity, in which gravity exerts its influence through warps and curves in the fabric of space and time,” Brian Greene, a physicist at Columbia University, said in a video for the World Science.

After Einstein’s death, the scientific community discovered that black holes do exist, and there are countless such black holes spreading throughout the universe.

On April 10, the genius’s century-old theory of general relativity was further reaffirmed—the existence of the gravitational and light-sucking cosmic objects was reported to be true.

“Today, general relativity has passed another crucial test, this one spanning from horizons to the stars,” Avery Broderick, Event Horizon Telescope (EHT) team member of the University of Waterloo and the Perimeter Institute for Theoretical Physics in Canada, said during a press conference in Washington, D.C.

“You can see the ring Einstein’s relativity predicts,” Vincent Fish, a research scientist at MIT’s Haystack Observatory in Westford, and also one of the 200 scientists who was involved in the project, told the Boston Herald. “You know exactly how big that ring should be. This was the first opportunity to test that hypothesis.”

Dimitrios Psaltis, Professor of Astronomy and Physics at the University of Arizona, and EHT project scientist, said in a press release: “The Event Horizon Telescope allows us for the very first time to test the predictions of Einstein’s General Theory of Relativity around supermassive black holes in the centers of galaxies. The predicted size and shape of the shadow theory match our observations remarkably well, increasing our confidence in this century-old theory.”

“If immersed in a bright region, like a disc of glowing gas, we expect a black hole to create a dark region similar to a shadow—something predicted by Einstein’s general relativity that we’ve never seen before,” Heino Falcke of Radboud University, the Netherlands, chair of the EHT Science Council, said.

Some Refute Einstein’s Theory

Despite the theory that shot Einstein to fame, some scientists have said the theory doesn’t explain everything, and requires revision.

Speaking about gravity, Austrian physicist Andrea Ghez, who led a 20-year-long black hole experiment, told Express News: “You can hark back to the days of Newton—who had the previous best description of gravity—and at some point we realized we had to move beyond Newton, to get a more complete vision.”

Ghez added: “As we explore these more and more extreme conditions we see that there is something missing.

“the closer you get to the heart of the galaxy, the shorter the time scales become.”

In terms of light, central to Einstein’s Theory of General Relativity is that the speed of light is constant everywhere.

One counter theory by researchers suggests that the speed of light is varied, and that light traveled faster in the wake of the Big Bang—a significant blow to Einstein’s theory.

“The idea that the speed of light could be variable was radical when first proposed, but with a numerical prediction, it becomes something physicists can actually test. If true, it would mean that the laws of nature were not always the same as they are today,” cosmologist and theoretical physicist João Magueijo told news.com.au.

Location of the Historic Finding

The black hole that was discovered resides at the heart of a huge galaxy known as Messier 87 or M87, near the Virgo galaxy cluster, 55 million light years from Earth.

The first snapshot of the black hole was captured by scientists using a global network of eight linked telescopes that were stationed over five continents in April 2017 for a week-long observation of black holes, according to Event Horizon Telescope.

“This is an extraordinary scientific feat accomplished by a team of more than 200 researchers,” said Sheperd Doeleman, director of the EHT Collaboration.

The enormous black hole captured in the image is predicted to have a mass 6.5 billion times bigger than our sun. Researchers believe it may be the biggest black hole that can be viewed from Earth.

“M87’s huge black hole mass makes it really a monster, even by supermassive black hole standards,” Sera Markoff, an astrophysicist at the University of Amsterdam, told The Verge. “You’re basically looking at a supermassive black hole that’s almost the size of our entire Solar System.”

https://www.theepochtimes.com/historic-image-of-black-hole-said-to-prove-einsteins-theory-of-relativity_2876829.html