- UID
- 783519
- 在线时间
- 小时
- 注册时间
- 2012-7-19
- 最后登录
- 1970-1-1
- 主题
- 帖子
- 性别
- 保密
|
235.Macho
1980's, BP proposed a way of determining whether the dark halo constituting the outermost part of the Milky Way galaxy is composed of MACHO's(massive compact halo objects).
BP: if true => MACHO would drift in front of a star in the Large Magellanic Cloud =>
Astronomers agree: The g of a MACHO would cause the star's light rays to bend =>
the star would temporarily appear to brighten -- microlensing
Sone astronomers: many stars are of intinsically variable brightness => not necessarily microlensing
However,
intrinsically variable stars:different colars of light are affected differently
Microlensing: all colors are equally affected
Moreover, it is unlikely that a star in the LMC will undergo microlensing more than once because the chances are low.
Magellanic Cloud 麦哲伦云
intrinsically -- by natural character
|
|