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What about the universe?





  Star on a Rainy Night: Called eXtreme Deep Field (XDF), this image was assembled by combining 10 years of Hubble Space Telescope photographs taken from spots in the sky with about 10,000 galaxies. The universe is unimaginably large and continues to grow.


© NASA; ESA; G. Illingworth, D. Magee, and P. Oesch, University of California, Santa Cruz; R. Bouwen …
Called eXtreme Deep Field (XDF), this image was assembled by combining 1

0 years of Hubble Space Telescope photographs taken from spots in the sky with about 10,000 galaxies. The universe is unimaginably large and continues to grow larger.

The universe doesn't look right. Suddenly it seems. ,, from blows.

This is a strange message coming from astronomers and physicists who wonder if they should revisit space history.

The universe is unimaginably large and continues to grow larger. But astronomers cannot agree on how fast it grows – and the more they study the problem, the more they disagree. Some scientists call this a "crisis" in cosmology. A less dramatic term in circulation is "Hubble's constant tension."

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Nine decades ago, astronomer Edwin Hubble showed that the universe is about as large as he supposed so far – and the whole set and the Kabul is expanding. The speed of this extension is a number called the Hubble Constant.

However, this is a slippery number. Measurements using different techniques produce different results and the numbers show no sign of convergence, even when the researchers refine their observations.

No one panics. On the contrary, theorists are intrigued. They hope that Hubble Constant's confusion is a harbinger of a potentially major discovery – some "new physics."

"Whenever there is a discrepancy, an anomaly, we are all very excited," says Catherine Mack, a physicist at North Carolina State University who co-authored a recent paper covering the issue.

The Hubble constant is a central feature of any theory of the evolution and ultimate destiny of the universe. This number may have zero effect on a person's daily existence, but many are cosmologically.

Where does everything go? How will it end? That's a big question, "said Mac.

A widely supported estimate of space expansion uses background radiation that penetrates space – light emitted when the universe was young. This gives Hubble a constant of 67 kilometers per second. (The parsex is just over three light-years away. According to this estimate, a galaxy one million parsecs from Earth moves 67 kilometers or about 42 miles per second and a galaxy twice as far away at 134 kilometers in second.)

But d a carefully calibrated light-based measurement emitted by exploding stars supernovae came out with a Hubble constant of 73. [19659015] "NASA. This planetary nebula is located in the constellation Aquarius, about 650 light-years away. This object is often photographed by amateur astronomers because of its bright colors and ominous resemblance to a giant eye. "height =" 250 "src =" http://img-s-msn-com.akamaized.net/tenant/amp/entityid/AAJG3a7.img?h=250&w=300&m=6&q=60&o=f&l=f "width = "300" />

© NASA / JPL-Caltech / University of Arizona / NASA / JPL-Caltech / Univ.of Ariz.
An infrared image of the Helix Nebula from NASA's Space Telescope. This planetary nebula is located in the constellation Aquarius, about 650 light-years away. This object is often photographed by amateur astronomers because of its bright colors and ominous resemblance to a giant eye.

These are not horseshoes or grenades: Closing doesn't count. People want the real, real, expanding Hubble Constant universe and no one is inclined to round it to the nearest 10.

This summer, as leaders in the field gathered in Santa Barbara, California to discuss "tension" , physicist Wendy Friedman of the University of Chicago presented a new estimate of the constant, which was based on the study of red giant stars. Her number: 70. But the defenders of 67 and 73 held their position. The tension remained. Friedman told the Washington Post, "There can't be three different numbers."

There is actually more than that. On October 23, researchers at the University of California at Davis published a paper looking at three gravity lenses – in which massive galaxies function as magnifiers for things behind them in deeper space. Their number is 77.

Some of the measurements may be based on erroneous assumptions. Imagine two high-speed rifles that give strikingly different measurements of Max Sherzer's fastball. One obvious, boring explanation is that one of the speeds must be recalibrated.

For example, astronomers may not have considered in a way that cosmic dust may interfere with observations, which would not be the first time. But the more delicious option is that something new must be discovered about the way the universe has evolved.

One idea that was floating around was that there might be something called Early Dark Energy that would distort the appearance of background radiation.

"The new physics may be that there is some form of energy that has acted in the earliest moments of the evolution of the universe. You will get an injection of energy, which then has to disappear, "Friedman said.

"If this is new physics, it's so exciting," says Joe Dunkley, a Princeton professor of physics. But she added: "I just don't want to jump into the idea that this is new physics. I am more skeptical of our ability to understand our measurement uncertainty. "

The Hubble constant measurement requires knowing the distance to the objects we observe in space. This is difficult. At first glance, it is impossible to tell if a star is unusually bright because of its absolute brightness or simply because it is relatively close.

A modest number of relatively close stars change their apparent position against the background of distant stars and galaxies as the Earth orbits the Sun. This allows for triangulation and accurate measurement of their distance. This is the first step of the remote ladder used by astronomers; the higher barbells are not as strong.

The most reliable "standard candles" for measuring cosmic distances are the Cepheid variable stars, which pulsate in brightness. In the early 20th century, Henrietta Swan Leavit, then an obscure employee of the Harvard College Observatory, discovered that inherently brighter stars had longer periods. This insight – the law of Leviticus – allows astronomers to know the absolute luminosity of Cepheid, and then to judge the distance to the star based on how bright or pale it looks.



  Night sky star: The Andromeda Galaxy is about 2.5 million light-years away. Andromeda is the closest galaxy to us.


© NASA / JPL / California Institute of Technology / NASA / JPL / California Institute of Technology
The Andromeda Galaxy is about 2.5 million light-years away. Andromeda is the closest galaxy to us.

In 1924, Edwin Hubble announced that he had found a variable star Cepheid in the Andromeda spiral nebula. This revealed that Andromeda is not a cloud of material lurking in our own galaxy, but rather a separate galaxy, a huge whirlwind of stars at great distances. Countless mysterious nebulae observed by astronomers have suddenly revealed their true nature as galaxies scattered in a very large universe.

At the end of this decade, Hubble and his colleague Milton Humson discovered that the light from distant galaxies was red-shifted, meaning that these galaxies were moving away from us. Moreover, the red shift increased with distance. The universe was telling us it was expanding.

(One of the common misconceptions is that these galaxies fly in space far from each other. But space itself expands, like a stretched tuft. And just to be clear: The Hubble Constant in question is the rate of expansion in ours The "local" universe, not the speed of expansion when it first emitted background radiation billions of years ago, over time, the Hubble constant is not constant.

Another surprise came in 1998. The orthodox view of cosmology was that expanding

Theorists are gradually building up a standard model of cosmology, in the standard model only about 5 percent of the universe is made up of ordinary matter – of which they are rocks, trees and frogs and humans made, The other 25 percent, approximately, is dark matter that does not emit radiation and is known only by the way its gravity affects the motion and configuration of galaxies. The rest is dark energy, the driving factor for accelerating space expansion.



  Fireworks in the Sky: The Cancer Nebula, which spans about 10 light-years, is one of the most intricately structured and dynamic objects ever seen. At its center lies a pulsar, a neutron star as massive as our sun, but only the size of a small city, NASA says.


© NASA / ESA / JPL / Arizona State University / NASA / ESA / JPL / Arizona State Univ.
The Cancer Nebula, which spans about 10 light-years, is one of the most intricately structured and dynamic objects ever seen. At its center lies a pulsar, a neutron star as massive as our sun, but only the size of a small city, NASA says.

At the dawn of the 21st century, this standard model appears to have passed all observational tests. And any discrepancies in the Hubble Constant measurement will certainly be corrected with additional observations, scientists suggest. They even nailed the age of the universe exactly: 13.8 billion years.

"We felt really good," says Adam Rees, a professor of physics and astronomy at Johns Hopkins University, who shares the 2011 Nobel Prize in Physics for opening the acceleration of the universe. He added to the joke, "We should stop taking data."

Riess continues to study supernovae and refine his estimates of Hubble Constant. His last published number is 73.5, plus or minus 1.4. And Riess points out that a completely different technique for twisting seven gravity lenses has given Hubble an average score of 73.7.

Meanwhile, the estimates of the team behind the Planck Space Telescope studying space microwave background radiation continue to be centered at 67.

So the discrepancy persists. That leaves open, Riese said, the excruciating possibility: "No one is wrong. Something else is going on in the universe. "

He warned against trying to intuit what this could be.

"We are connected to our intuition to understand things around us," Ries said. "Most of the universe is made of things that are completely different from us. This adherence to intuition is often violently unsuccessful in the universe. “

joel.achenbach@washpost.com


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