The Large Magellanic Cloud (LMC) completes a rotation every
250 years. It takes our Sun the same time to rotate around the Milky Way
Galaxy. Using the Hubble Telescope, NASA has been able to, for the first time,
measure the rotation rate of this galaxy precisely because the stars move in a
clock-like movement. Hubble recorded the individual movement of stars, which
are located 170,000 light years away, during a seven-year period. Nitya
Kallivayalil of the University of Virginia says that knowing the rate of
rotation offers insight as to how a galaxy formed. The rate of rotation can
also be used to calculate the mass of the galaxy.
The LMC is a nearby galaxy. The reason it’s important to
study it is because it is very near to our own galaxy. It’s easier to study the
LMC because you’re looking out to it; it’s so difficult to study our own galaxy
because you’re studying it from the inside therefore everything is spread out
form each other. In the past, astronomers have calculated the rate of rotation
of a galaxy using the Doppler effect. To calculate the rate of motion, they
used the motion that Hubble recorded and also used the Doppler effect. Then
they combined the information together in order to find out what the rate of
rotation was for the galaxy.
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9:05 AM
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NASA
is currently developing an Asteroid Redirect Mission (ARM) that will identify,
capture, and then redirect the asteroid somewhere else. ARM will use solar
electric propulsion and the Space Launch system. The asteroids will be captured
by the men in the Orion spacecraft and then examined. After the examination,
they will be redirected to orbit the Earth’s moon in order to investigate the
asteroid more in the future. There are not many known candidates for ARM
because most are too large to be redirected by a spacecraft. Paul Chodas, a
senior scientist for Near-Earth Object Program Office at NASA’s Jet Propulsion
Laboratory, said that the ideal size of an asteroid that they are looking for
is about 40 ft in diameter. The problem is that this is very small for an
asteroid, therefore it is very difficult for even the most powerful telescopes
to detect the asteroid. The best time to detect an asteroid is when it is near
Earth.
Asteroids are found by scientists
who scan the skies looking for star-like objects that move slightly every hour.
Asteroid surveys find hundreds of moving objects, but only a small percentage of
these objects are new discoveries. After they are found, the coordinates of the
moving object are sent to the Minor Planet Center in Cambridge, Massachusetts.
It is there where they determine if it is already an existing asteroid or not.
Then the information on the asteroid is published with data about its orbit and
brightness.
Sources:
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8:23 PM
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About 40 years ago, astronomers saw
a long ribbon of gas stretching almost halfway across the Milky Way Galaxy.
This ribbon of gas was named the Magellanic Stream after what astronomers
thought it came from: the Small or Large Magellanic Cloud. Until now, astronomers
were uncertain from which cloud the ribbon came from. But now they know for
certain that it came from the Small Magellanic Cloud about 2 million years
ago.
This was reported in
The Astrophysical Journal. They found
this out by studying the composition of the Magellanic Stream. Most of the
strips components matched those of the Small Magellanic Cloud. But, parts of
the Stream closer to the Clouds found a higher abundance of sulfur, which
matches with the Large Magellanic Cloud. This suggests that this strip was
ripped off of the Large Magellanic Cloud more recently. Spacetelescope.org
gives us more insight on the topic.
The Magellanic Clouds, are two
dwarf galaxies that orbit our galaxy. While it was unknown from where the
Stream came from, computer mode
ls of the Stream predicted it solely cam from
the Small Magellanic Cloud because of its weaker gravitational pull compared to
the large Magellanic Cloud. In order to find out the abundance of elements in
the stream, they had to look through the ultraviolet part of the
electromagnetic spectrum. Only the Hubble telescope is capable of doing this.
Source:
Astronomy
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9:03 AM
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