欢迎来到VOA在线收网 www.voa365.com
当前位置:VOA NEWS > VOA慢速英语 > 科学报道 >

How Does One Find a Meteorite?

2014-08-12 10:23来源:未知

音频下载

 
Perseids Viewing Map.  Check out the meteor showers where you live!

Perseids Viewing Map. Check out the meteor showers where you live!

Editor's Note: The annual Perseid meteor shower will peak in the skies over Earth on the night of Aug. 12-13. Despite a bright moon supermoon, there should still be a good show from this prolific shower.

 

Much of the world can see Perseids any time after full dark, with peak viewing projected early on the morning of Aug. 13, between 3:00 to 4:00 a.m., your local time. Addtional information can be found from the NASA website.

 

And now, for a story on meteorite from George Putic and Anna Mateo.

 

Space rocks often enter the Earth’s atmosphere.  But they usually explode and burn before falling to the ground.  About 70 percent of our planet is covered with water.  As a result, most meteorites falling from the sky disappear on the oceansfloor.  We would not know about them if it was not for an international agency.

 
Reporters gather around a piece of a meteorite, which according to local authorities and scientists, was lifted from the bottom of the Chebarkul Lake in Chelyabinsk, Russia, Oct. 18, 2013.Reporters gather around a piece of a meteorite, which according to local authorities and scientists, was lifted from the bottom of the Chebarkul Lake in Chelyabinsk, Russia, Oct. 18, 2013.

You may remember the meteorite that exploded last year 23 kilometers above Chelyabinsk, in RussiaScientists estimate it was about 18 meters long before it fell to EarthThey also think it had a mass of about 10,000 tons.  

 

Many people would have died if the meteorite fell in a populated area.  Luckily, it did not.  Instead it broke apart mid-air and most of the pieces fell into Lake Chebarkul.  But that is a little too close for some people.

 

The Comprehensive Nuclear-Test-Ban Treaty Preparatory Commission is a group based in Vienna, Austria.  It says the Earth is visited by meteorites more often than we know.   

 

The group records explosions made by meteorites that enter Earth’s atmospherePierrick Mialle works for the commission, also known as the CTBTO.  He is an acoustics expert, specializing in the study of sounds

 

He says since meteorites are sometimes entering the atmosphere, they are creating loud air bursts.

 

The commission controls sensors and other equipment that watch for possible violations of the Nuclear Test ban treatySome of the devices are seismic, meaning they measure the movement of the EarthOthers are hydrostatic, meaning they measure the movement of the Earth’s water.  The Commission also uses ultrasound and radioactivity sensors

 

Between 2000 and 2013, the CTBTO recorded 26 powerful explosions of large meteorites entering the atmosphere

 

The B612 Foundation also studies meteorite impacts.  This group estimates at least four of those 26 explosions were stronger than the nuclear bomb that destroyed Hiroshima.

 

In addition to loud noise, explosions create low frequency infrasoundSound waves can travel very long distances at such low frequencies.  But human beings are unable to hear them.

 

CTBTO stations as far away as the Antarctica recorded the explosion of the Chelyabinsk meteorite.

 

Mr. Mialle says listening stations operate anywhere from four to 15 high-technology sensors.  He says that the sensors work like large microphones

 

They are called micro barometer because they measure micro fluctuations of the atmosphere.  It’s like a large microphone except there’s no membrane.”

 

He adds that some of the explosions are hard to identify immediately after they are recorded.

 

“For instance, the first time we had this, what was later called the Super Bolide of North Pacific, in the first few weeks all that was known was a large event in the middle of the Pacific.  But we didn’t know what it was.”

 

The commission keeps contact with other agencies, such as the American space agency, that follow meteoritesSpace agency officials later confirmed that the mysterious explosion was caused by a meteorite.

 

When complete, the CTBTO system will have 337 stations worldwide.  And these stations will be listening for nuclear explosions and other loud sounds in the atmosphere.

 

(责任编辑:v365)
最新新闻
  1. 网传日月光Q4产能利用率降至70%
  2. 新型存储器已经开始增长,到20
  3. 市场人士透露:联发科在汽车芯片
  4. 【VOA在线闲聊】三星收购Arm会步英
  5. Nikola召回迄今为止生产的93辆Nik
  6. 蚂蚁数科两项区块链专利完成一对
  7. 蔚来申请注册“NIO CERTIFIED 蔚来官
  8. 获小米超千万投资 改装车公司工
  9. 法拉第未来首款电动汽车FF 91再次
  10. 消息称LG显示计划明年生产920万块
  11. 宝马面向欧洲市场推出最小的跨界
  12. 美国副总统哈里斯承诺就电动汽车
  13. 知情人士透露称马斯克和推特CE
  14. 因苹果缩减订单 台积电或修改明
  15. LG推出一项新技术,以开放局域网
  16. 小米13正式上线:骁龙8Gen2发布1
  17. 米家3 KG迷你洗衣机售价699元
  18. 苹果公司官方非常兴奋:印度将生
  19. 中国广电在全国31个省区开通广电
  20. 华为 Mate 50 Pro国外上市:售价远高
  21. 特斯拉柏林超级工厂回收工厂发生
  22. 华为 Mate 50原价4999
  23. iPhone 14销售比上一代下降了11%
  24. 2021至2025中国台湾将投350亿元新台
  25. 华为Mate50Pro预定5 G芯片,苹果公司
  26. 锐龙7000核显性能实测 单核及多核
  27. 索尼PS5最新更新:6 nm制程功率与
  28. 华为会议马上就要开始了!一种全
  29. 小米再次成为了冠军!该系列产品
  30. 还能吸收病毒?!戴森首个产品也
  31. 小米又推出了一款新产品,售价
  32. Imagination携手百度飞桨创建Model
  33. 奔驰要不要再加价?2024将发布
  34. TikTok在英国或被罚款2900万美元 被
  35. iPhone15PM改用 ULTRA:笔记本和 iPa
  36. 因库存不断提升存储芯片持续降价
  37. 预计小米Civi2将推出五款新产品
  38. 可靠商务桌面电脑推荐:联想M4
  39. 受飓风影响:NASA撤回阿尔忒弥斯
  40. 《三体》影迷们疯狂了!
  41. 4090设计实在是太离谱了!
  42. Meta试图Facebook和Instagram账户添加到
  43. 苹果公司在技术上遭受重大挫折,
  44. 我国成功发射遥感三十六号卫星,
  45. 骁龙8Gen2+120 W快速充电!小米13系
  46. 屏幕下手机价格大跌,灵动岛安卓
  47. 亚马逊宣布下月举办新会员促销活
  48. 酷睿i9-13900K预告片,5.8 GHz稳定!
  49. 美国流媒体巨头Netflix宣布在芬兰
  50. 外科手术机器人 商业化将加快世