| 查看: 530 | 回复: 4 | |||
[交流]
Everyday News-NASA Mission Finds Fewer Near-Earth Asteroids Than Expected
|
|
Bad news for little princes—there may be fewer Earth-neighboring asteroids for them to live on than thought. According to results released today by NASA's Wide-Field Infrared Survey Explorer mission, an infrared satellite that's been keeping its eye on asteroids zipping within 200 million kilometers of Earth's orbit, there are close to 20,000 near-Earth asteroids between 100 meters and 1 kilometer in diameter (shown on left). That's down from old guesses of about 35,000 (right). And nearly 15,000 of those rocks, which are big enough to crush an entire city, have yet to be discovered. The researchers also confirmed that astronomers have identified more than 90% of the nearly 1000 big asteroids of the dino-extinction variety. That's too late for Tyrannosaurus rex but perhaps not too late for us. So maybe we ARE alone.  |
回复此楼» 猜你喜欢
生物学308求调剂（一志愿华东师大）
已经有6人回复
-
调剂求收留
已经有7人回复
-
272分材料子求调剂
已经有36人回复
-
275求调剂
已经有8人回复
-
一志愿211，化学学硕，310分，本科重点双非，求调剂
已经有20人回复
-
070300化学学硕311分求调剂
已经有19人回复
-
材料与化工调剂
已经有13人回复
-
材料与化工调剂
已经有33人回复
-
复试调剂
已经有7人回复
-
一志愿哈工大 085600 277 12材科基求调剂
已经有17人回复
2楼2011-10-01 22:10:32
my bandeng 3楼2011-10-01 22:13:27
★
xia_chong(金币+1): Hello! Welcome to English Cafe! 2011-10-02 14:23:03
xia_chong(金币+1): Hello! Welcome to English Cafe! 2011-10-02 14:23:03
 |
4楼2011-10-02 11:40:54
xia_chong
金虫 (文坛精英)
- ESEPI: 43
- 应助: 0 (幼儿园)
- 贵宾: 1.591
- 金币: 10270.8
- 散金: 2377
- 红花: 34
- 沙发: 160
- 帖子: 12455
- 在线: 1941.8小时
- 虫号: 804303
- 注册: 2009-07-06
- 性别: GG
- 专业: 粒子物理学和场论
- 管辖: English Cafe
5楼2011-10-02 14:22:44
5