To do away with Apophis
as a threat,
we would need to slow it down enough to change
its orbit so that it is completely within the Earth's orbit
and thus never a threat again. According to NASA, it's mass is about
27,000,000,000 kg or 27 million tonnes. To change its speed by even one
km per second would take about 27,000 gigajoules of energy imparted
with 100% efficiency. That's about 7.5 gigawatt hours of energy. In
practice, even a VASIMR rocket engine is
nowhere near
100% efficient. I have no idea how much fuel a
chemical
rocket would take. At best I think we may change its direction
slightly, but
to significantly alter its speed is a huge task.
But even if it is slight, it takes a
huge amount of
energy. I am stunned by peoples'
lack of comprehension of
what is involved. Beyond the fuel needed to do the job of
moving it, there is the fuel needed to launch
that
off the Earth into space, then the fuel needed to
get to
the candidate, then the fuel needed to slow down and rendezvous with
it. To launch a payload into space takes
many times the mass
of the payload in fuel and to achieve escape velocity, many
more times that as well. Then, once there, it would be
like
towing a large barge with a row boat. Chemical rockets would
require the most mass to be launched, but an ion engine would either
need to be extremely powerful or work for a very long time. The idea of
using a "tug boat" in the form of a large mass to gravitationally pull
it in a new direction is
very far fetched in practice.
It would need a huge mass to be launched and guided into the right
position, and then a
huge amount of energy expended over time
to do the job. Too little and it would simple fall toward the asteroid,
too much and it would just fly away into space. The closer it is, the
more effect it would have, but then its propulsion would have to be
diverted to miss the object, so as to not push back on it in the
opposite direction to what is desired. It would be
like
trying to tow a car with a bicycle using a piece of string as a tow line.
Pull too little and do nothing. Pull too hard and snap the string. The
only benefit to that method, over planting a rocket on the object
directly, is that ["tug boats"] could be used on a spinning object.
Many of these ideas sound great in theory, but
in practice
are close to ridiculous. Usually
the amount of
energy involved is deceptively huge. We'd be as well off
hoping to one day have a Star Trek-like warp drive and tractor beam,
both of which may be a VERY long time coming. I hope the Russians learn
something from the effort, and I rest assured it will be pretty well
ineffective,
and I am further sure that by having an inconsequential effect on it,
it
won't change the chances for a collision in the least.
-
John_with_a_B, Space.com, Dec. 30 2009
"Before
landing on an asteroid, a spacecraft must enter its orbit, rather than
simply whizzing by. That means matching the object's speed and
direction of motion, which in most cases would require
burning too much rocket fuel to be practical. The only way
round this would be if the asteroid's motion happened to be very
similar to Earth's at the time of its closest approach...ground-based
telescopes are hampered because asteroids in orbits similar to Earth's
are often hidden by the glare of the Sun...The rotation rate of most
asteroids is unknown, but any fast-spinning objects will be
off limits because they would be difficult for astronauts to hang onto...There
are more problems to overcome. Small, irregularly shaped asteroids have
lumpy gravity fields, so an orbiting spacecraft would follow a chaotic
trajectory, making navigation much trickier than around Earth or the
Moon...It would be wise to send robots before humans. We don't have the
sort of data that you might want before you send an astronaut."
-
NewScientist.com, April 28, 2010
"The capability to deflect an impact-threatening
asteroid needs to be developed and demonstrated,
and that work needs to be done cooperatively with
[NASA and] other space agencies."
-
Apollo astronaut Rusty Schweickart, a founder of B612 Foundation, Wired.com,
Dec. 30, 2009
A huge asteroid, 350 meters in diameter, will
come dangerously close to Earth, risking a lethal crash with our
planet…A celestial body named Apophis - asteroid 2004 MN4 - is
considered the greatest space danger for Earth. In 2029 it will pass
within 30 thousand kilometers of Earth, closer than some orbital
satellites. Anything could happen to change its trajectory and direct
it to Earth. The trajectory of the celestial body is expected
to change so that the collision is quite likely, the head of Federal
Space Agency, Anatoly Perminov, said in an interview with the
Voice of Russia Radio. He mentioned the data
comes from research by an unnamed scientist claiming the
accident is almost inevitable. If the meteor hits
our planet, a territory the size of France would turn into a devastated
desert. They are on the way to create a spaceship that will divert the
threatening asteroid from its orbit. The exact nature of the device has
not yet been unveiled. After the solution is found,
the plan is to attract other space states to finance the
project, the USA and China among them. "We need some sort of
international action. People have wondered 'what do we do with
asteroids?'" Jeff Manber said.
-
rt.com - Russia Today Dec. 31, 2009
Russian Scientists Brace For
Approaching Asteroid…Russia's space agency has been holding
meetings about Apophis - the asteroid due to pass close to Earth in
2029. If it is not diverted, a collision could potentially kill
millions, scientists say.
"The probability of a collision with the Earth was
very high, about 1 to 30. The collision of such a
large body with our planet will cause great damage," explains Boris
Shustov, Director of the Institute of Astronomy…An asteroid with a
diameter of 300m is a cause for concern. Scientists insist that the
critical moment will come in 2029 when Apophis passes so close to Earth
that it will be visible to the naked eye…If the asteroid were to
collide with Earth, the blast would be a hundred thousand times more
powerful than the atomic bombing of Hiroshima. The collision could wipe
out countries and produce a destructive chain reaction in the
environment. Blowing up Apophis with nuclear weapons to prevent the
impact has been ruled out.
Valery Menshikov, of the Russian Academy of
Cosmonautics, says scientists should be careful not to underestimate
the asteroid's danger. "There are a large number of asteroids revolving
around the Earth and crossing its orbit. We often overlook them,"
Menshikov said. "In October an asteroid
exploded over Indonesia at the height of 10-12km. The total
explosion power was equal to over 50 megatons, which can be compared to
three Hiroshima explosions," Menshikov added.
-
rt.com - Russia Today Jan. 20, 2010
Space.com
Jan. 22, 2010

MSNBC.com
Jan. 23, 2010

NewsScientist.com
Jan. 21, 2010

.
Are we ready to act if an asteroid or
comet were to pose a threat to our planet? No, says a new report from
the National Research Council. Plus, we don't have the resources in
place to detect the possible dangerous objects out there. The
$4 million the U.S. spends annually to search for NEOs is insufficient
to meet a congressionally mandated requirement to detect NEOs that
could threaten Earth. Congress has not appropriated new funds
for the survey nor has the administration asked for them. "To
do what Congress mandated NASA to do is going to take new
technology, and bigger telescopes with wider fields," said
Don Yeomans, Manager of NASA's Near Earth Object Program, "Once these
new facilities are in place, the rate of warnings will go up
by a factor of 40."
"There's the geopolitical misconception
that NASA is taking care of it. They aren't," said former
astronaut Rusty Schweickart, "and this is an international issue."
Schweickart said making decisions on how to mitigate the threat once a
space rock already on the way is too late, and that all the decisions
of what will be done, and how, need to be made now. "If we
procrastinate and argue about this, we'll argue our way past the point
of where it's too late and we'll take the hit." But the report put out
by the NRC stresses the methods for asteroid/comet defense
are new and still immature…none is now ready to implement on
short notice, the report says. Civil defense and kinetic impactors are
probably the closest to readiness, but even these require
additional study prior to reliance on them.
UniverseToday.com
- Jan. 22, 2010
There are huge numbers of asteroids that come
close to Earth's orbit. Millions of them are large enough to do serious
damage in an impact. A US National Research Council panel recommends
setting up an international body that would be prepared
to spring into action and defend the planet if an asteroid is
discovered on an impact course. The international body would
be "composed of representatives of nations concerned with
this problem and willing to invest in preparedness
for a damaging collision", the report says. Radar observations by the
giant Arecibo telescope in Puerto Rico allow trajectories to be
determined most precisely, but uncertain funding threatens this
capability. The US should initiate a research programme to
develop deflection technologies and to better understand impact effects like tsunamis.
NewScientist.com
- Jan. 22, 2010
NewsScientist.com
Jan. 21/22, 2010


.
[Asteroid 2010 AL30's] unusual orbit seems
ingeniously designed to evade our surveys. It is likely that a handful
of objects large enough to cause harm are hiding under similar
circumstances. Smaller asteroids - which can still damage Earth if they
span at least 30 to 50 metres [98 - 164 ft.]- are usually too
dim for telescopes to detect except during brief close
approaches to Earth. Asteroids with non-synchronous orbits can also
hide. Those with orbits mostly interior to Earth's orbit spend most of
their time in the glare of the Sun as seen from Earth, so telescopes
have trouble spotting them. [They] would be easier to spot if
a telescope were positioned closer to the Sun. Such a telescope would
also make it harder for asteroids to hide in synchronised orbits…the
cost of such a mission would be high…Even the Wide Field
Infrared Survey Explorer (WISE) will only be able to spot a
small fraction of any mid-sized asteroids in these orbits…the
majority of hidden asteroids are too small and dim to be detected until
they are practically on top of us - regardless of their orbits. "The
sad part is," says Tim Spahr of the Minor Planet Center, "the
bulk of the [asteroid] population is invisible to us most of the time."
COMMENTS:
That's interesting if even a 50
meter [164 ft.] rock was to hit earth it would be a
equivalent to about 45 million tons of TNT being detonated. That is
very similar to the explosion size of the largest nuke ever tested,
which was the equivalent of 50 million tons of TNT. If detonated in
London, a bomb that size would take out the entire city. That would be
over 7 million lives lost. There are much larger asteroids hiding out
there that we don't know about. - Derek Rhode
We've had equal-size objects pass even
closer, and they've all been quickly forgotten. Most people simply
focused on the fact that the object did
disintegrate before impacting the ground.
- Tavi Greiner
NewScientist.com
- Jan. 21, 2010
If we're going to protect the Earth from
an asteroid, we need to find the dangerous ones whizzing
about in the emptiness of space…Better telescopes than we
currently have will be needed. "The equipment isn't even
built yet," said U. of Maryland astronomer Michael A'Hearn, "our
estimates of the risk could easily be wrong by a factor of two or
three." Finding and tracking [smaller asteroids] will require
new telescopes, like the Large Synoptic Sky Survey and Panstarrs, neither
of which currently has the funding to complete construction.
COMMENTS:
Is this a real problem? When was the Earth hit by a large
piece of rock from space? I know we have small stuff quite
often. But this does not seem to be a
frequent thing. - jescott418
[NOTE: Not true. We're only told
it's not frequent by H.I.M.M.]
This is not one of those
I-told-you-so situations. There will be no one left to tell. I want a
different, saner planet to go to, inhabited by humans that work
together towards humane and scientific advancement, understanding that
ensuring continued existence of a livable planet is first priority.
There won't be enough money in the budget till after we all fry. I live
on a planet run by unaware lunatics controlling each country.
- ThoughtEyeNew
Wired.com
- Jan. 22, 2010
"Humans
haven’t got their priorities right…they
don’t know how to act. They act just like the pigs that run these
places, you know,
countries. They base everything on the status thing, that’s why
there're people starving." - Jimi Hendrix
ScientificBlogging
Jan. 22 2010

Wired.com
Jan. 22, 2010

Space.com
Jan. 22, 2010
Notice
the Headline in Green at Bottom -
It's the Reason for Private Condos In Orbit
.
Less than $1 million is currently set
aside to research ways to counter space rocks that endanger
the Earth - measures like developing the spacecraft and technology to
deflect incoming asteroids - a report by the National Academy of
Sciences states…NASA is ill-equipped to catalogue 90 percent
of the nearby asteroids that are 460 feet (140 meters) across or
larger…United States should be planning more methods of defending Earth
against an asteroid threat in the near-term…decades of notice are
required to build and launch spacecraft to push an asteroid clear of
Earth…Recent
meteor bursts over the United States have highlighted the
potential danger of even smaller asteroids…Even small space rocks pose
a threat to people and property on Earth…According to the report,
current long-term projections estimate that there could be up to 100
fatalities a year caused by space rock impacts.
COMMENTS:
This is ridiculous. There isn't
a single documented case of anyone being killed by a space rock in
10,000 years. The Earth is well-protected by the greater attraction of
Jupiter [for asteroids]. - gslippy
[NOTE: Both claims are false: a house was hit in India,
not to mention the 1200
Americans killed at Peshtigo, or the 1871 Chicago fire
deaths, and near 300,000 killed by the 2004
Christmas Day Impact in the Indian Ocean. This comment
opinion is molded by the disinformation spin
of H.I.M.M. Jupiter is no "protection" for Earth, the fact is
that it flings rocks at
us.]
At present we cannot stop an
asteroid from hitting our planet. That is the sad, sad fact. We go
insane over climate change, which is maybe less damaging, it has
happened before. People can survive it. Civilization
can survive it. - Valcan
They should make an orbital platform
with a variety of weaponry such as super powerful lasers. Of course it
could be hacked and used by a psycho to kill everyone or something.
- DatSpaceMan
Space.com
- Jan. 22, 2010
"We talk about Star Wars as if
all we have to do is decide to go and we do, but the physics haven't
been invented yet to do Star Wars."
-
Senator John Glenn, News Hour, PBS June 6, 1996
Space.com
- Jan. 29 2010

International experts [are] engaged in a
three-year work plan on drafting international procedures for handling
the threat posed by the possible impact to Earth by an
asteroid…The Association of Space Explorers (ASE) looks forward to
spreading the results of the recent workshop and urges future
work within the U.N. and by the world's space agencies to develop the
capacity to deflect a NEO headed for Earth…"We came together
to work through the challenges which will be faced by the
international community in deciding how to respond to such an
event," said Apollo astronaut, Russell Schweickart…"the nations of the
world are discussing how to prevent these events."
The ASE report also recommended setting up a Mission Planning and
Operations Group to plan, organize, and conduct any necessary
missions to threatening asteroids…There needs to be
a coordinated, global response to asteroid threats…to find
the most efficient and effective way of doing just that,"
said Advisor Brian Weeden.
COMMENTS:
Oh great, the U.N. is on it. I
feel so secure now. When they detect an asteroid on a collision course
with Earth, they plan to deflect it with a strongly worded letter.
- ZenDraken
Look up and wave at it. We can't stop a
rock 40m across traveling 30k mph. Assuming it's ice, and spherical,
the asteroid would weigh-in at 30,000 TONS.
K=.5*M*V^2
M=30000 tons = 27,215,542 kg
V= 30k mph = 13,411 m/s
K=2,447,424,578,191,091 Joules = 2.4 x 10^15
One megaton is equivalent to 4.18 x
10^15 joules, so we are looking at 1/2 of a megaton explosion, focused
in one direction, not radial like a nuke, and that's for a relativly
small 40m asteroid made of ice. Make it a reasonable-to-large size,
made out of nickle and iron, and just watch the show. -
Eddie_42
THIS IS A WARNING! A very large
asteroid is on it's way! - Aerospace_Cadet
Space.com
- Jan. 29, 2010
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