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Unit 7: Astrophysics Page 28
There have been several satellites away from the sun. It takes Eris
specially created to observe the 560 years to complete one trip
sun, including Ulysses (launched around the sun. Sedna is the
1990, studied solar wind and coldest object we’ve found in our
magnetic fields at the poles), solar system. It’s a tiny rock (930
Yohkoh (1991-2001, studied x-rays miles across) about 8.4 billion
and gamma radiation from solar miles away from the sun,
flares), SOHO (launched 1995, discovered in 2003. It would be
studies interior and surface), and like trying to spot a single grain of
TRACE (launched 1998, studies the sand in California from the Moon.
corona and magnetic field).
Gerard Kuiper (1905-1973) is
Kuiper Belt and Beyond known as the father of planetary
science for his discoveries of
The Kuiper Belt is an icy region moons in the solar system as well
that extends from just beyond as detecting atmospheres on Titan
Neptune (from 3.7 billion miles to and Mars.
7.4 billion miles from the sun).
Most objects in this region take The Oort cloud lies just beyond the
hundreds of years t orbit the sun Kuiper belt, housing an estimated
from this distance. This is where 1 trillion comets. The Oort cloud is
most comets and asteroids from so large that it occasionally gets
our solar system hang out. The stirred up by nearby stars (like
largest object out there is Eris, but Alpha-Centauri, our nearest
we’re still finding new ones all the neighbor). When this happens, the
time. gravitational effect can either
bump the comet’s orbit toward our
sun, or sling it forever out of our
system toward other stars. Jan
Oort (1900-1992) was one of the
world’s top astronomers who first
figured out that our solar system
was surrounded by a cloud of
comets. He also figured out the
where the center of our galaxy is
(in Sagittarius).
Eris is the largest known dwarf
planet (the other dwarfs are Ceres
and Pluto), orbiting 10 billion miles
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