APOD:2015.9.26

Sweet丿Kim (金) 天王星
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发表于:2015-09-29 12:45 [只看楼主] [划词开启]

星系M31与M33 

影像提供与版权: 

Malcolm Park (North York Astronomical Association)

说明: 

在地球天空中分隔约14度─28个满月─的螺旋星系M31(左)和M33,以及我们的银河系,皆是本星系群的大型成员。这幅结合多部窄角及广角相机的组合影像,除了清楚呈现了这两个相邻大星系螺旋臂的细微结构之外,它们也看似以仙女座亮星奎宿九 (Mirach)为平衡点,分落在此星的二侧。


只不过,奎宿九离太阳只有200光年远,仙女座大星系M31的距离为2百50万光年,三角座大星系M33约有3百万光年远。虽然M31与M33看来相隔很远,实际上它们以引力互锁进行争战。事实上,电波天文学家找到的线索指出,它们之间可能以一道中性氢气桥相连,为过去曾发生近距离接近的迹证。根据量测和现行的引力模拟预测,银河系、M31和M33之间都会发生近距离接触,在未来数十亿年之间可能会合并。

__________________________________________________________________________________


M31 versus M33 

Image Credit & Copyright: Malcolm Park (North York Astronomical Association)

Explanation: Separated by about 14 degrees (28 Full Moons) in planet Earth's sky, spiral galaxies M31 at left, and M33 are both large members of the Local Group, along with our own Milky Way galaxy. This narrow- and wide-angle, multi-camera composite finds details of spiral structure in both, while the massive neighboring galaxies seem to be balanced in starry fields either side of bright Mirach, beta star in the constellation Andromeda. Mirach is just 200 light-years from the Sun. But M31, the Andromeda Galaxy, is really 2.5 million light-years distant and M33, the Triangulum Galaxy, is also about 3 million light years away. Although they look far apart, M31 and M33 are engaged in a gravitational struggle. In fact, radio astronomers have found indications of a bridge of neutral hydrogen gas that could connect the two, evidence of a closer encounter in the past. Based on measurements, gravitational simulations currently predict that the Milky Way, M31, and M33 will all undergo mutual close encounters and potentially mergers, billions of years in the future.




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分类: 宇宙观光属
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