to travel a 3.1-billion-mile journey deep into the Asteroid Belt,
to have a look at this, Ceres, it's the biggest thing in the Asteroid Belt,
with a diameter of 590 miles, a surface area four times larger than Texas, and
a mass about one-fourteenth that of Pluto, though it's technically an asteroid and a dwarf planet, some
scientists regard Ceres to be a real plane, the tiniest in our solar
system, Dawn is travelling at about 450 mph toward the largest unexplored
object between the Sun and Pluto, in the late 1700s, astronomers wondered about
the large gap between Mars and Jupiter, Bode's
law predicted a planet should be
there, and in 1801, scientists finally found one, well sort of, for half a
century, Ceres was classified as a planet, then, as telescopes became better,
scientists found a number of smaller objects in a similar orbit, collectively,
those objects came to be known as the Asteroid Belt, and Ceres was reclassified
as an asteroid,
Ceres' identity was called into question again in 2006, when
scientists debated the status of Pluto and the definition of a 'planet',
planetary scientists like Sykes advocated
for the name to apply to any object that has enough gravity to be round, The
International Astronomical Union, however, defined a planet as something with
enough gravity to clear everything out of its orbit, Pluto failed that test and
so did Ceres, 'it would have been cool, because if Pluto were a planet, then
Ceres would have to be, too, says Sara
Seager, a planetary scientist at the
Massachusetts Institute of Technology,
so why the excitement about Ceres? beneath its surface,
Ceres may harbour a liquid ocean, that's exciting for biologists who are looking
for life on other worlds, because on Earth at least, everywhere there's water,
there's life, astronomers working on the Herschel Space Telescope in January
2014 reported detecting
water vapour in a few patches
around Ceres' mid-latitudes, something was
spraying water into the air in very low yet detectable amounts, no one knows
what the source is yet, it could be boring, such as ice sublimating into water
vapour, but the universe is full of surprises, if the vapour
jets of Enceladus and sulphur-belching
volcanoes of Io are any
evidence, Ceres could have cryovolcanoes that gush with water melted by the
heat of radioactive decay deep below the planetoids surface, Dawn is
currently the best and only means to find out more,
if you are still reading this is the plan, the Dawn spacecraft launched Sept. 27, 2007, since then, it has been moving in a spiral trajectory toward the outer solar system, it reached the protoplanet Vesta in July of 2011, and studied it for fourteen months, now, the spacecraft is about to reach its ultimate destination.
Here's the plan once it arrives:
- March 6, 2015: Dawn arrives in orbit around Ceres. (Note: Scientists don't know the exact nature of Ceres' gravity, and since gravity will affect the spacecraft's travel time, all subsequent dates are estimated.)
- April 23, 2015: The spacecraft initially orbits at 8,400 miles above Ceres. Here it starts taking pictures, analysing the planetoids surface, and looking for evidence of water vapour.
- June 10, 2015: Dawn descends to an altitude of 2,730 miles for a closer look.
- Aug. 15, 2015: From an altitude of 910 miles , Dawn extensively maps the surface of Ceres. It snaps photos from different angles, allowing researchers on Earth to gradually build a 3-D view of the landscape.
- Dec. 20, 2015: Dawn moves in to its closest orbit, just 230 miles above the surface—nearly 40 times nearer than its first orbit. “It will be like looking at a soccer ball seven inches from your eyes,” says Marc Rayman. From here, Dawn takes more detailed observations. It maps Ceres' gravity field, which should reveal how its mass is distributed in the interior (and possibly reveal a subsurface ocean). The spacecraft will also use gamma ray and neutron spectrometers, which measure the signature emissions from different elements in Ceres' crust and interior. This will tell us what Ceres is made of.
- June 2016: The mission ends. Though Dawn's fuel and solar panels may keep it alive for a few additional years, the spacecraft could continue to orbit Ceres for hundreds of years.
and most of us did not even know this was going on, the wonders of space.
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