Transcript File - Mrs. Phillips` Physical Science Webpage

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Asteroids and meteoroids are both fragments
of rock and are differentiated by size – bigger
than 100m with a mass over 10,000 tons is
an asteroid
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The Asteroid Belt, It’s Not What You Think https://www.youtube.com/watch?v=DrbCAoiyUNw
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There are hundreds of thousands of asteroids
Most lie within the asteroid belt, about
midway between Mars & Jupiter
One known asteroid has a retrograde orbit – all
others have prograde orbits
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The Trojan asteroids lie 60 degrees in front or
behind Jupiter in a delicate balance between
Jupiter’s gravity and the sun’s
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Jupiter’s or Mars’ gravity might deflect
an asteroid to a new orbit that crosses
the Earth’s orbit
http://www.youtube.com/watch?v=xNxYPpk6D1Q&sns=em
5 Ways to Stop a Killer Asteroid
http://youtu.be/cot680thsdQ
Gaia and the Killer Asteroids
http://youtu.be/Agdvt9M3NJA
Bill Nye – Could we Stop an Asteroid
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Icarus 1566 (named because at periphelion it
comes closer to the Sun than Mercury) and in
June 1968 it came close enough to Earth
(4mill miles) to become the first minor planet
to be tracked by radar; in June 2015 it came
approx 8.1 mill miles (passes Earth in June
at 9, 19 or 28 yr cycles)
http://youtu.be/cot680thsdQ
Gaia and the Killer Asteroids
http://youtu.be/Agdvt9M3NJA
Bill Nye – Could we Stop an Asteroid
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2002 MN - 73 meter-sized asteroid that on June
14, 2002 missed the Earth by only 120,700 km,
about one third the distance to the Moon.
The close approach was second only to the Earth
approach by the 10 meter-sized asteroid 1994 XM1.
Discovered on June 17, 2002 three days after closest
approach.
Its mass and relative velocity were in the same
general range as the object ascribed to the Tunguska
event of 1908, which leveled over 800 square miles
(2,100 km2) of trees in Siberia.
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Over 1400 of the Earth crossing asteroids are
designated as potentially hazardous – large
enough (larger than140m in diameter) and
will come within 7.5 million km of
Earth….their paths are on the next slide.
Between 2000 and 2010, about 200 that we
know of passed within this distance, 2 within
the orbit of the Moon.
Our closest predicted miss in the next
century is Apophis, a 350 m asteroid, in April
2029, which should pass about 30,000 km
away. EEEEEEEK!
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Every year about 3 asteroids do strike Earth
– most are just too small to cause much
damage, especially once they have gone
through our atmosphere.
― Most strike uninhabited areas
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Several satellites have flown by and sent
pictures back of asteroids over the years,
usually on their way to other destinations.
Galileo passed by Gaspra on the way to Jupiter in
1991 and Ida in 1993
▪ Ida has its own moon, Dactyl!
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Near Earth Asteroid Rendevous (NEAR)
spacecraft was sent specifically to visit Eros,
and stopped by Mathilde in 1997.
The decision was made for NEAR to land on Eros
at the end of the mission in 2001. It was not made
for this purpose, but succeeded and continued
sending data for 2 weeks after the landing.
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Satellite Dawn began orbiting the 2nd largest
asteroid in the asteroid belt, Vesta, in July
2011.
Vesta has a series of deep troughs that girdle its
equator.
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A dwarf planet is:
a celestial body orbiting a Sun that is massive
enough to be rounded by its own gravity but
which has not cleared its neighboring region of
planetesimals and is not a satellite.
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Dwarf planets can be found in the asteroid
belt or trans-Neptunian, in the Kuiper belt.
Asteroid Belt Dwarf Planets
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In July 2012, Dawn moved on toward the
largest of all of the asteroids in the asteroid
belt, the dwarf planet Ceres, which it reached
in March 2015.
---Bright spots believed to be reflections from salt deposits
https://www.youtube.com/watch?v=dzAOXdeJJb0
---From 240 miles away
Trans-Neptunian Dwarf Planets
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Eris was believed to be the largest of the asteroids and is a
dwarf planet, possibly up to 27% larger than Pluto, but
New Horizons confirmed that Pluto is larger in 2015.
 Discovered
in 2005
 Has its own
moon,
Dysnomia
Trans-Neptunian Dwarf Planets
• Eris
was originally named 2003UB313, then
was unofficially named Xena when it might
become a planet. Upon the classification of a
dwarf planet, it was officially called Eris after
the goddess of strife and discord. Its moon,
Dysnomia, is named after Eris' daughter, the
goddess of lawlessness. (The actress that
portrayed Xena on TV was is Lucy
LAWLESS.)
• The discovery of Eris is directly responsible
for Pluto no longer being a planet in 2006.
Trans-Neptunian Dwarf Planets
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Haumea - is not spherical in shape, but it
meets the definition of a dwarf planet by
having reached hydrostatic equilibrium,
which usually results in a spherical shape.
Trans-Neptunian Dwarf Planets
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The provisional designation 2005 FY9 was given
to Makemake when the discovery was made
public. Before that, the discovery team used the
codename "Easterbunny" for the object, because
of its discovery shortly after Easter. In July
2008, it was given the name of a creator deity.
The name of Makemake, the creator of
humanity and god of fertility in the mythos of
the Rapanui, the native people of Easter Island,
was chosen in part to preserve the object's
connection with Easter.
Trans-Neptunian Dwarf Planets
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Pluto is a dwarf planet, demoted in 2006.
It is the largest of the dwarf planets, at 1,473 miles (2,370
km) in diameter, confirmed by the New Horizons mission in
August of 2015.
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http://m.space.com/29957-pluto-charon-fly-by-high-resolution-imagery-revealed-bynasavideo.html?cmpid=514630_20150715_49219956&adbid=10152944147996466&adbpl=fb
&adbpr=17610706465
http://solarsystem.nasa.gov/plutotime/
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A comet is a ball of ice that travels on a
highly elliptical orbit
Generally at least 1000m in size
When it nears the sun it develops a tail and a
coma, a gaseous cloud surrounding the
nucleus
http://youtu.be/OZlenAvqLCI
Pan-STARRS from March 2013
Masses are believed to be similar in range to small asteroids
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The ion tail is formed by ionized atoms that
have lost their electrons. It is highly
influenced by the solar wind
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The dust tail is made up of fragments of dust
that follow the orbit of the comet, giving it a
curved shape
Masses are believed to be similar in range to small asteroids
Tail always points away from
the sun due to the solar wind
– this was the reason that
astronomers first began to
infer the existence of the
solar wind
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Many countries have sent missions to study
comets, with varying success.
Stardust in 2004 got within 150km of P/Wild 2
collecting particles in a aerogel dust collector and
returned to Earth in 2006 with the materials
▪ First evidence for organic material apparently formed in
deep space
▪ Presence of silicate materials that we had up until then
believed could only form at high temps, which calls into
question models of the formation of the solar system
Deep Impact in 2005 launched a projectile into a
comet, blasting gas and debris, video taping and
collecting the gas that was ejected from the
impact
Allowed a view of the internal composition of the
nucleus of the comet
Confirmed the presence of water, ice and many
organic molecules
Rosetta – ESA
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Launched in 2004 to rendevous with Comet 67P/Churyumov-Gerasimenko
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Arrived at the comet
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August 6, 2014 and began sending back pictures
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No ice found on surface
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Hydrogen and oxygen gas found at surface and in coma
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Darker than charcoal black
Rosetta – ESA
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Philae launched and landed from Rosetta on November 12, 2014
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Made last, futile attempt to contact Philae in Jan 2016
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FIRST EVER LANDING ON A COMET!!!
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Strange sounds have been recorded from coming the comet by Rosetta– interactions from the solar wind and the
coma of the comet - possibly material being shed from the comet becoming ionized by the plasma. LISTEN!
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http://www.iflscience.com/space/rosetta-s-comet-sounds-lot-predator
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The Kuiper belt is a region that lies outside of
Neptune to about 100 times the distance of Earth
from the Sun. Comets that originate in this area
generally remain outside of the jovian planets, but
may be kicked out of orbit by Neptune and sent in
toward the Sun.
Called short-period comets, they have orbits of less than
200 years and stay within Pluto’s orbit
Tend to be prograde
Generally in same elliptical plane as the planets
Over 1000 known Kuiper belt objects, including Pluto
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The Oort Cloud is a spherical region of
comets that surrounds the solar system out
to more than 1,000 times the distance
between Pluto and the sun.
This was reasoned due to the fact that we observe
only a tiny portion of the orbit of the long-period
comets; so for every one we observe, there must be
tons we don’t…..thus there must be a huge cloud
of comets far beyond the orbit of Pluto….
First suggested in the 1950s
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Most are long-period orbits, highly elliptical,
going well past Pluto on their treks, taking
hundreds of thousands of years or longer to
complete an orbit.
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Halley’s Comet
Short period comet captured by Jupiter’s orbit
Returns about once every 76 years
Last here in 1985-1986
http://youtu.be/C8zV1xiGqf4
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A meteor is simply a piece of an asteroid or
meteoroid or comet that interacts with or
atmosphere…usually a meteoroid because
they are so common
As the meteor moves through the
atmosphere, the friction heats the molecules
and atoms, exciting their electrons, which
emit light when they return to ground state.
Often the remains of broken up comets,
therefore they often travel in meteoroid swarms
& in nearly the same orbit as the parent comet
resulting in yearly or twice yearly meteor
showers
• Meteor showers are named for their radiant, the
constellation they appear to come from
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The Perseids seem to come out of the constellation
Perseus every year in August
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When a meteor survives its trip through the
atmosphere intact and hits the ground, you
have a meteorite.
Smaller than about 1m across and about 1 ton in
mass usually burn up; larger make it to the
surface
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The Barringer Crater meteoroid was about
50m, around the size of the high school
The Tunguska explosion of 1908 was from a
30m rock
Ann Hodges – the only known
human being ever hit by a
meteorite – November 30, 1954
in Sylacauga, Alabama
https://www.youtube.com/watc
h?v=1kvHl5Qcnzc
https://www.youtube.com/wat
ch?v=pFBtfR54Svk
https://www.youtube.com
/watch?v=wZ2XXa5oFhw
This is a piece of meteor 2011 EO40 that exploded about 25 miles above Chelyabinsk,
Russia, early in the morning on February 15, 2013.
The power of the blast is estimated at over 20 x the strength of the atomic bomb dropped
on Hiroshima
This piece, recovered from Lake Chebarkul in Oct 2013, weighs at least 1257 lbs