Beyond
the galaxy’s center lie mostly uncharted swaths of space. But now
astronomers have found some landmarks: five stars roughly 75,000
light-years from Earth. The discovery should help astronomers map the
largely unexplored far side of the Milky Way and understand the nature
of the enigmatic dark matter thought to hold galaxies together.
The five stars are all Cepheid variables, whose brightness fluctuates steadily. Astronomers use Cepheids as distance markers because the brighter the star, the slower it pulsates. By measuring a Cepheid’s period and how bright it appears from Earth, astronomers can calculate its distance; if the star is in another galaxy, then researchers know how far away the galaxy is as well.
Reposted by Louis Sheehan
The five stars are all Cepheid variables, whose brightness fluctuates steadily. Astronomers use Cepheids as distance markers because the brighter the star, the slower it pulsates. By measuring a Cepheid’s period and how bright it appears from Earth, astronomers can calculate its distance; if the star is in another galaxy, then researchers know how far away the galaxy is as well.
Reposted by Louis Sheehan
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