发信人: dreammh (☆梦幻☆蒸发☆), 信区: Astronomy
标  题: Re: 5小时后小行星撞地球
发信站: 水木社区 (Tue Oct  7 07:25:01 2008), 站内

轨道模拟的撞击前从小行星看地球 时间比较长 多等一会能看出变化
http://orbit.psi.edu/?q=node/22

注意这个小行星在撞击前1个小时就进地影了! 这个可能也是以前再做小行星观测的人也
都没见过的

离地面80-100km发光 可见范围大概从南欧到中非



昨天晚上我们系（亚利桑那大学天文系）巡天的镜子发现了一个新的近地小行星 今天中午得到的临时编号
2008TC3 到了下午2点多的时候已经有了76个天测位置 轨道定出来之后发现撞击
地球的概率是100.0%

目前的轨道对应的撞击地点是苏丹北部 北纬21度东经33度附近 撞击时间是
世界时10月7日02:46分

不过万幸的消息是这颗小行星绝对星等只有30等 对应直径在10米一下 可能只有
2米之类的 进入地球大气的时候估计会非常壮观 不过按照目前的大多数燃蚀模型
这颗小行星(12km/s载入 18度仰角)都会在大气中彻底销毁 不过也有模型的结论
是说会有落到地表的陨石 至于最后到底怎么样 恐怕只有看了才知道了 目前唯一
严格确定的就是撞击这个事件本身

无论如何 这是人类历史上第一次在地外天体撞击地球前观测到它 确定轨道 并得
到撞击解 也再次提醒人类撞击的威胁: 如果这次发现的是2公里的小行星而不是
2米的 那么..........

我刚才成心没写小行星的大小 就是为了吓唬吓唬人再说 呵呵 不过其实网上已经
可以查到相关信息了 中午的时候NASA已经发布了消息 现在在NASA和一些国外的
爱好者网站上应该都能找到了

另外下午系里的邮件组里收到了某未发表版本的NASA新闻稿 里面说NASA之所以要
出来公布这个消息 是因为大半夜的天上突然起个燃烧弹 怕苏丹当地有人认为是
对方武装挑衅然后出别的事... 不过我刚看了一下这句话在NASA正式发布的新闻稿
里被删掉了

[ 本帖最后由 meteorobs 于 2008-10-7 13:03 编辑 ]

晕，一次自然事件也能有政治、军事上的利用价值......

这个小行星的名字起的好

好壮观的流星啊！

引用:

原帖由 bonjovi90 于 2008-10-7 10:09 发表
这个小行星的名字起的好

是我刚看到这个消息时突发奇想加上去的。。。这么个天外来客坠落苏丹，那个国家不红才怪呢。。。

Update - 6:45 PM PDT (1 hour prior to atmospheric entry)

Since its discovery barely a day ago, 2008 TC3 has been observed
extensively by astronomers around the world, and as a result, our orbit
predictions have become very precise. We estimate that this object
will enter the Earth's atmosphere at around 2:45:28 UTC and reach maximum
deceleration around 2:45:54 UTC at an altitude of about 14 km. These times
are uncertain by +/- 15 seconds or so. The time at which any fragments might
reach the ground depends a great deal on the physical properties of the object,
but should be around 2:46:20 UTC +/- 40 seconds.

怎么样，那边有照片吗

那我就火星一下吧。

[ 本帖最后由 meteorobs 于 2008-10-7 12:45 编辑 ]

不知道苏丹红把苏丹红了没有?

等待图片，呵呵

真壮观啊！

Asteroid to burn up before hitting Earth

Mon Oct 6, 5:43 PM ET



WASHINGTON (Reuters) - A tiny asteroid discovered earlier Monday by an Arizona observatory will hit Earth's atmosphere over Sudan in a few hours but will burn up before it can hit the ground or endanger aircraft, astronomers said.

The asteroid will create a large fireball at about 10:46 p.m. EDT (0246 GMT on Tuesday) as it burns up, the team at the Harvard-Smithsonian Center for Astrophysics said.

"We want to stress that this object is not a threat," said Dr. Timothy Spahr, director of the International Astronomical Union's Minor Planet Center at Harvard in Massachusetts.

"We're excited since this is the first time we have issued a prediction that an object will enter Earth's atmosphere," Spahr added in a statement.

The asteroid, known as a meteoroid, is between 3 and 15 feet in diameter.

"A typical meteor comes from an object the size of a grain of sand," said Gareth Williams of the Minor Planet Center. "This meteor will be a real humdinger in comparison."

It will be visible from eastern Africa and will evaporate over Sudan, the scientists said.

"We really hope that someone will manage to photograph it," said Williams.

(Reporting by Maggie Fox, editing by Will Dunham and John O'Callaghan)

Mon Oct 6, 5:24 PM ET



WASHINGTON - Astronomers say a small asteroid is about to make a fiery but harmless dive into Earth's atmosphere early Tuesday morning over Africa.

Harvard scientists announced late Monday afternoon that the unnamed asteroid will burn up in the sky, making a fireball that people in northern Africa should be able to see. The rock is between 3 feet and 15 feet in diameter. It's expected to enter Earth's atmosphere above Sudan at 10:46 p.m. EDT Monday, which is just before dawn in Africa

Harvard astronomer Tim Spahr said the asteroid is so small it can't reach the ground and will not hurt anyone. Astronomers have tracked the sky for years looking for potential comets and asteroids that regularly pelt Earth, but this is the first one they saw coming.

Small Asteroid Predicted to Cause Brilliant Fireball over Northern Sudan

Small Asteroid Predicted to Cause Brilliant Fireball over Northern Sudan
Don Yeomans
NASA/JPL Near-Earth Object Program Office
October 6, 2008
A very small, few-meter sized asteroid, designated 2008 TC3, was found Monday morning by the Catalina Sky Survey from their observatory near Tucson Arizona. Preliminary orbital computations by the Minor Planet Center suggested an atmospheric entry of this object within a day of discovery. JPL confirmed that an atmospheric impact will very likely occur during early morning twilight over northern Sudan, north-eastern Africa, at 2:46 UT Tuesday morning. The fireball, which could be brilliant, will travel west to east (from azimuth = 281 degrees) at a relative atmospheric impact velocity of 12.8 km/s and arrive at a very low angle (19 degrees) to the local horizon. It is very unlikely that any sizable fragments will survive passage through the Earth's atmosphere.

Objects of this size would be expected to enter the Earth's atmosphere every few months on average but this is the first time such an event has been predicted ahead of time.

Update - 6:45 PM PDT (1 hour prior to atmospheric entry)

Since its discovery barely a day ago, 2008 TC3 has been observed extensively by astronomers around the world, and as a result, our orbit predictions have become very precise. We estimate that this object will enter the Earth's atmosphere at around 2:45:28 UTC and reach maximum deceleration at around 2:45:54 UTC. These times are uncertain by +/- 15 seconds or so. The time at which any fragments might reach the ground depends a great deal on the physical properties of the object, but should be around 2:46:20 UTC +/- 40 seconds.


http://neo.jpl.nasa.gov/news/news159.html

2008年10月07日10:53  来源：科学网

   长期以来，天文学家一直在监视天空以求发现可能撞击地球的小行星，现在他们终于发现了一个，而且它来得是如此之快！根据美国宇航局（NASA）喷气推进实验室天体动力学家Steven Chesley的计算，苏丹当地时间10月7日早上5点46分，北京时间10月7日10点46分，近地天体（NEO）8TA9D69将撞击苏丹上空的大气层。

    不过不用担心，尽管这一直径大约为2米的小行星的撞击力相当于1000吨TNT炸药，但它将会以火流星的形式在大气中分解。意大利比萨大学天文学家Andrea Milan说：“它对地面的损害被认为为零。”

    行星天文学家David Morrison表示，“这是小行星撞击首次被预报”，反映了不断增加的世界范围内监测NEO的能力。第一次，人们无需再惊恐地抬头望天，望着外太空物质撞向地球。 （科学网 梅进/编译）

[ 本帖最后由 meteorobs 于 2008-10-7 13:10 编辑 ]

另据北京天文馆网站消息：国际小行星中心所在的哈佛史密松天体物理中心宣布，昨天（10月6日）由美国亚利桑那大学小行星项目刚刚发现的小行星2008 TC3有99.8%—100%的概率将于北京时间2008年10月7日上午10:46与地球相撞。

北京天文馆小行星和流星领域的研究人员表示，由于小行星的直径预计只有1—5米，在苏丹北部上空进入地球大气层的这颗小行星将在大气层中燃烧，可能产生碎裂，非常可能会有陨石掉落地面，但不会在地球上产生任何破坏。在非洲东部地区的观测者在天气条件良好的情况下将观测到一个非常亮的由东北到西南方向的火流星，甚至观测到陨石雨。类似大小的小行星每年都会光顾地球，但这次是天文学家第一次在这些小天体撞击到地球之前发现它们。北京天文馆正在负责建设的北京地区火流星监测网在2008年年底落成之后将在相关领域继续推进我国的小天体研究工作。（朱进）

参见哈佛史密松天体物理中心网站：Boulder—sized Asteroid Will Burn Up in Earth's Atmosphere Tonight


http://www.sciencetimes.com.cn/htmlnews/2008/10/211687.html

楼主的第一幅照片好像是卫星解体的照片

当时发时就说了，因为当时没有可以利用的现场图片，于是“火星地”示意了一下。。。

达尔富尔解决了！哈哈

苏丹红？哈哈