Posted on 07/15/2008 11:01:48 AM PDT by Raineygoodyear
YOU'D think that by now we'd have a firm grip on the trajectory of the solar system's most worrisome chunk of rock. In fact we have only a hazy understanding of how likely the asteroid Apophis is to strike Earth. What's more, budget cuts may shut down the telescope that could clarify the situation. Since Apophis was discovered in 2004, asteroid-watchers have known that it has a slim chance of hitting Earth in 2036. At 270 metres wide, it is too small to rival the object that wiped out the dinosaurs, but it could cause devastating tsunamis were it to hit the ocean. Worrying as this is, we have been able to take comfort in the computed probability of impact, which is just 1 in 45,000. Now it seems the true risk is unclear, thanks to minute effects that the calculations didn't take into account. "You really can't estimate. Fastest spinning asteroid spied by amateur stargazer 17:48 28 May 2008 The newly discovered asteroid, known as 2008 HJ, was first discovered on 24 April by a robotic telescope in Socorro, New Mexico. It was then flagged up as a potential observing target by the Faulkes project's website.
(Excerpt) Read more at space.newscientist.com ...
But the one thing they do know if that Global temperatures will increase 0.345 degrees Celsius in 2011. The model says so.
Oh great, now it's bound to land on my garage.
Time for Bruce Willis to suit up.
In 2035 they will discover that NASA made a math error. Ooops too late.
After “Live free or Die hard”, he should be placed on it!
I see you rounded 0.3447 up...
Hmmmm, I didn't know Bush would again be president in 2036?
I never believe a single thing they report about space exploration its all bunk, like we didn’t “know” they were going to “find water on mars”. Sheese, they know nothing, and what they think they know now will be disproven in 5 years (but still other information that will later be disproven).
He's not, but:...
What's more, budget cuts may shut down the telescope that could clarify the situation.
Budget cuts during his administration...therefore, Bush's fault ; )
The Hammer Of God.
great point!
I didn’t read the whole article because I’m not a subscriber.
It sounds like they are talking about unmodeled errors, which I find surprising. I suppose radiation pressure is hard to model accurately, but the effect is pretty small. Gravity is very, very accurately known. The NASA website has a little chat up about modeling errors and how they calculate the “probability” that an asteroid will hit the Earth.
Basically, they take a draw from a population that has the same distribution as the supposed uncertainties as the object being predicted. [Same covariance matrix.] (I do not know if that includes radiation pressure) and propagate that state vector forward using Newton’s Laws, with corrections for General Relativity to the period of interest. This process is repeated millions of times and the resulting population characterizes our knowledge of the state (position and velocity) of the object in the future, including the average and the covariance. (Covariance is a fancy name for uncertainty.)
The method can be validated by taking older state vectors and comparing them the present positions, or by taking a current state vector, propagating it and seeing how well it predicts the future.
This kind of calculation is the bread and butter of dynamists and I would be surprised if they messed it up so badly as to be off by “millions of miles” when the predicted uncertainty is “tens of thousands of miles”.
Sound like rank alarmism to me.
Relating skeptism about astrodynamics to skeptism about Global Warming is unfair, imho. There are several widely accepted, well validated, solar system dynamical models. They are mutally consistent (give similar results) and have been validated by observations.
Global warming models are not well validated (they cannot, for instance, predict the past), not mutually consistent and are contradicted by daily weather reports.
A creationist will be along shortly to tell us the solution to the N-body problem is in the Bible.
All the tricky parts cancel once you define PI as exactly 3.
“YOU’D think that by now we’d have a firm grip on the trajectory”
I hope this is the same trajectory math BoyClinton sold the ChiComs.
Sorry if I panicked anyone -- just getting a jump start on a headline we're likely to see soon. :-)
“Just let me know when it’s time to dig my Skylab helmet out of storage.”
Reminds me of a cartoon I saw in 1979 in which a White House spokesman was asked what is President Carter doing to ensure safety in the event Skylab were to crash into the US. The spokesman says the president has a plan....
In the next panel you see Carter standing out on the White House lawn wearing a baseball catcher’s gear. Pretty funny.
The models calculate in double precision. They could have shown the prediciton out to the billionth of a degree.
And it's precise. If no parameters are changed, the computers will exactly duplicate the double precision number.
Accurate? No. Double precision wild ass guess.
Bring on the Asteroid, at least we will finally be rid of idiotic liberals, God's way of cleansing the world maybe? Just asking.
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