3994 - ASTEROIDS - There is one following us? Our space exploration is just beginning to learn about the near-Earth asteroids. There are millions of them that orbit with us around the Sun. Maybe we should begin tracking their trajectories and predicting any collisions. Then what?
-------------- 3994 - ASTEROIDS - There is one following us?
- Don’t look
now but there is an asteroid following us right now. It is far enough behind that it is actually
ahead of us in our orbit. It is called a
‘Trojan Asteroid’ caught in the Lagrangian Point between us and the Sun.
-
- What
happens when the gravity of the Earth exactly matches the gravity of the Sun
and the Centripetal Force the object in Earth’s orbit? They all balance and cancel out to zero
force. The asteroid’s orbit is caught in
this null of forces.
-
- There are 5
“Lagrangian Points” around the Earth.
The points L4 and L5 lie just 60 degrees ahead and 60 degrees behind the
Earth. Asteroid “2010TK” is trapped in
Lagrangian Point L4, 60 degrees ahead in Earth’s orbit around the Sun.
-
- This
asteroid is about 1,000 feet in diameter and some 50,000,000 miles away. It is very dim at 20.6 Magnitude
brightness. Its reflectivity is
10%. Also called ‘albedo’, the Moon’s reflectivity is 7%. The asteroid does not stay exactly at the
Lagrangian Point but oscillates in a tad-pole shaped loop that it traverses
every 365 years. The closest point it
reaches to Earth is 12,400,000 miles.
-
- This
asteroid is not economical for us to visit because it orbit inclines by 21
degrees to our plane of orbit. This
would require the rocket spacecraft to have a velocity of 21,000 miles per hour
to reach it. There are other near-Earth
asteroids that can be reached with rocket velocities of only 9,000 miles per
hour.
-
- We have
visited another asteroid named “21 Lutetia”.
The Rosetta spacecraft passed within 1,965 miles of Lutetia in July,
2010. The “ Dawn” spacecraft visited 4
Vesta asteroid that same month.
-
- Lutetia is a piece of planetisimals that was
around during the formation of the planets some 5 billion years ago. It orbits the Sun at 2.4 Astronomical Units
which puts it at the near-side of the Asteroid Belt between Mars and
Jupiter. It takes 3.8 years to complete
one orbit.Lutetia is odd shaped 75 miles by 62 miles by 46 miles dimensions.
-
- Its composition is “enstatite chondrite”,
which is pretty uncommon and thought to
be the starting composition of the terrestrial planets. Its surface is loosely aggregated dust
particles 50 to 100 micrometers in size.
Its density is 3.4 grams per cubic centimeter. ( water is 1.0). This heavier density tells astronomers that
the rocky body probably maintained its primordial state.
-
- Lutetia’s surface has 350 impact craters
ranging in diameter from 600 to 55,000 meters.
Its surface is intersected by fractures, scarps, and grooves that are
thought to be caused by internal fractures.
-
- This asteroid has likely survived intact
from the beginning of the Solar System.
Astronomers expect it to have a metallic core, a mantel, and a surface
crust that has never melted. They think
it formed some 3,000,000 years of the formation of the Solar System.
- Who is
watching these asteroids to learn if one is about to collide with the Earth?
- No one
really!
- Yet, we can
record over 1,000,000 asteroids over 40 meters in diameter orbiting in our
vicinity as we orbit the Sun. One of
these asteroids struck the Earth in 1908 over the Siberia in Russia. Its devastation to that unlucky wasteland was
150 time larger than the destruction power of the Hiroshima atomic bomb.
-
- Who is
going to find, track, and predict the trajectories of all of these asteroids?
It seems that is a national priority that ought to be funded. Some astronomers have tracked all those
asteroids they could find over 1,000 meters in diameter. Their calculated that these trajectories are
not expected to hit us over the next 100 years.
-
- However,
thousands of smaller asteroids remain on the loose. Anyone could be big enough to destroy a
country if it hit land. An asteroid
hitting the oceans could create a tsunami wave that would devastate all its
coastal cities.
-
- We have the
infrared telescopes that could detect these asteroids but there is no funding
for such a project. We need the
leadership in Washington that is not worrying about this years election,
rather, worrying about how to protect our planet for the next generation, both
economically and physically.
-
- We need to
fund projects now that experiment with what to do after we find an asteroid
heading our way. It would be a dumb idea
to just blow it up because it would just change the impact from a bullet wound
to a shotgun blast. We need to
experiment with a ‘controlled way’ to move an asteroid off its trajectory.
-
- Can we learn
how to deflect an asteroid. The
dinosaurs did not fund such a project and look what happened to them. The evolution of the Solar System is still
happening. Do we participate or just let
nature take its course? An announcement
will be made shortly, stay tuned.
-
May 10, 2023
ASTEROIDS - There is one following
us? 1375 3992
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--------------------- --- Wednesday, May 10, 2023
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