WAITING FOR DAWN
Ceres the largest object in the main Asteroid Belt is
waiting for the arrival of Dawn as early as March 6th, 2015. This
icy mass was originally called a planet when discovered in 1801 by an Italian
astronomer named Giuseppe Piazzi. Since that time and with some debate its
definition was changed in 2006 by the International Astronomical Union and
Ceres is now classified as a dwarf planet.
If you are not familiar with Ceres, here are some
interesting facts:
·
It is fourteen times smaller than Pluto.
·
It is 590 miles in diameter.
·
It constitutes about 30% of the mass of everything in
the asteroid belt.
·
It completes a rotation every 9 hours and 4 minutes.
·
It is believed to have a rocky core with an icy
mantle.
·
Its surface can warm to -36 degrees Fahrenheit.
·
It has an atmosphere but it is very weak.
·
It has a mysterious bright ‘white’ spot.
While the world awaits the first visit to Pluto this
July by another mission, the space probe Dawn is nearing the end of its
seven-year, 3.1 billion mile journey deep into the Asteroid Belt. I’m,
wondering about the nature of this alien world. What does it look like? Will
there be mountains, craters, and “cryovolcanoes” that spew frozen water miles
into its thin atmosphere? What is that bright ‘white’ spot anyway? What lies
below that frozen surface…a liquid ocean? Although the chance of life existing
on Ceres is very low, scientists claim that if there is water there may be
life. Nevertheless, it’s exciting to imagine a mysterious, strange-looking sea-monster
world.
Dawn could change the shape and scope of future space
missions. Dawn has already visited Vesta, the second largest object in the
Asteroid Belt a few years ago and will enter the orbit of Ceres in early March.
Travelling at 24,000 miles per hour is possible due to its twin ion thruster
engines where xenon atoms are bombarded with electrons to form ions. The ions
are charged and shoot out the engines up to 90,000 miles per hour. However, the
thrust effect is minimal on the probe because of a zero-gravity, frictionless
environment. Does this sound like science fiction to you? Perhaps you’ve
already seen it in Star Wars, when Darth Vader’s TIE fighter would speed
through the galaxy. Just like Darth Vader’s super-speedy vehicle, Dawn uses
solar energy to feed electrons into its power-hungry engines. I believe this
technology to be a stepping-stone to Mars.
My reference
sources: www.earthsky.org, www.space.com, www.planetary.org, www.popsci.com,
http://solarsystem.nasa.gov, http://news.discovery.com
To find
out what Dawn discovered about Vesta you can see what Emily
Lakdawalla, of the Planetary Society has to say in her Blog at http://www.planetary.org/blogs/emily-lakdawalla/2014/10091306-what-did-dawn-learn-at-vesta.html.