综合一区欧美国产,99国产麻豆免费精品,九九精品黄色录像,亚洲激情青青草,久久亚洲熟妇熟,中文字幕av在线播放,国产一区二区卡,九九久久国产精品,久久精品视频免费

   

Astronomers puzzled by giant void

(AP)
Updated: 2007-08-24 10:59

WASHINGTON -- Astronomers have stumbled upon a tremendous hole in the universe. That's got them scratching their heads about what's just not there. The cosmic blank spot has no stray stars, no galaxies, no sucking black holes, not even mysterious dark matter. It is 1 billion light years across of nothing. That's an expanse of nearly 6 billion trillion miles of emptiness, a University of Minnesota team announced Thursday.

Astronomers have known for many years that there are patches in the universe where nobody's home. In fact, one such place is practically a neighbor, a mere 2 million light years away. But what the Minnesota team discovered, using two different types of astronomical observations, is a void that's far bigger than scientists ever imagined.

"This is 1,000 times the volume of what we sort of expected to see in terms of a typical void," said Minnesota astronomy professor Lawrence Rudnick, author of the paper that will be published in Astrophysical Journal. "It's not clear that we have the right word yet ... This is too much of a surprise."

Rudnick was examining a sky survey from the National Radio Astronomy Observatory, which essentially takes radio pictures of a broad expanse of the universe. But one area of the universe had radio pictures indicating there was up to 45 percent less matter in that region, Rudnick said.

The rest of the matter in the radio pictures can be explained as stars and other cosmic structures between here and the void, which is about 5 to 10 billion light years away.

Rudnick then checked observations of cosmic microwave background radiation and found a cold spot. The only explanation, Rudnick said, is it's empty of matter.

It could also be a statistical freak of nature, but that's probably less likely than a giant void, said James Condon, an astronomer at the National Radio Astronomy Observatory. He wasn't part of Rudnick's team but is following up on the research.

"It looks like something to be taken seriously," said Brent Tully, a University of Hawaii astronomer who wasn't part of this research but studies the void closer to Earth.

Tully said astronomers may eventually find a few cosmic structures in the void, but it would still be nearly empty.

Holes in the universe probably occur when the gravity from areas with bigger mass pull matter from less dense areas, Tully said. After 13 billion years "they are losing out in the battle to where there are larger concentrations of matter," he said.

Retired NASA astronomer Steve Maran said of the discovery: "This is incredibly important for something where there is nothing to it."



Top World News  
Today's Top News  
Most Commented/Read Stories in 48 Hours
东乌| 巫山县| 高邑县| 庄河市| 全南县| 启东市| 西乡县| 克拉玛依市| 资兴市| 武清区| 固原市| 德保县| 广东省| 合肥市| 东海县| 梁河县| 夏河县| 福州市| 昭觉县| 郑州市| 阳城县| 峨眉山市| 扎鲁特旗| 德州市| 乐昌市| 得荣县| 塔城市| 闽侯县| 梁山县| 静宁县| 乌兰浩特市| 达州市| 米泉市| 山阳县| 苗栗县| 巴马| 石泉县| 平乐县| 将乐县| 孝义市| 大邑县|