Sunday, May 1, 2011
Why Some People Need to Refrain from Writing Science Content (3)
Another example of a person out of his depth showed up on one of the article discussion forums at salon.com. This guy, a "Mike Sulzer" challenged another commentator who had responded to an earlier poster on the fact that the rate of current consumption for the global population is equivalent to using up 1.5 Earth's worth of resources per year. That earlier person then noted the best way out was to use space exploration to find more habitable planets. After agreeing, the respondent said another reason to promote such space exploration was on account of a planet-killing asteroid strike at some point, wiping out the human species. Hence, not keeping all "eggs" in one planetary basket. Mike Sulzer then responded:
You're stupid! What I'm telling you is fact: we already know about 80% of the asteroids larger than 1 km in diameter. The big ones are hard to hide forever. There are very few of them and it is very unlikely one of the 20% in hiding will hit us, but we will know eventually.
Of course, this didn't satisfy the original poster, who fired back:
And I told you (based on info you linked on an earlier thread from a GEOLOGICAL site) you don't know dick or diddly. You didn't then and you don't now. This info from geology sites, as opposed to astrodynamic ones, is why you continue to babble clueless, idiotic rot.
First, we don't "know" all the Apollo, earth -crossers that can really terminate this little orb. That is pure bunkum. We know a few but our observational limits don't allow us to know all. Worse, many of the asteroid spotting sites have been shut down as a result of budgetary cuts and the Space Guard project itself is now in the dust bin.
Second, I already exposed your stupid little site for the half-baked and half assed thing it was by quoting it as indicating there was no real method for defleting LARGE asteroids even if we did detect them. All the methods they described hinged on the asteroids being small.
Lastly, I guess what,,...you're going to call Sir Martin Rees "stupid" too? He recently delivered a lecture asserting humanity may only have 50 years left before a monster asteroid strike of the type I described.
So, who was right? Well, Sulzer was certainly wrong. The asteroid Hermes passed within 500,000 miles of Earth in 1937 – a hair’s breadth by astronomical standards. Factor in multiple perturbations that can alter its orbit and one can easily arrive at a collision scenario on one of its next passes. Indeed, in 2003 it passed within 300,000 miles on a new pass. See:
As the preceding site notes, Hermes approaches Earth once every 777 days, and each pass presents an opportunity for closer approach if Earth’s perturbations are large enough on it. As the site also notes, the asteroid came harrowingly close in 1937, 1942, 1954, 1974, 1986 then 2003. And this is but one good sized object.
To therefore be dismissive of the potential of asteroid future impact is the height of hubris and stupidity. We are living in a self-created fantasyland if we think our atmosphere can protect us from all these objects. For example, it would offer about as much resistance to Hermes as butter would to a machete.
Sulzer's other claim concerning 20% of the larger asteroids "hiding" is also a misconception. It's not so much that they're 'hiding' but that our observational technology can't keep up with them in the first place. Thus, each year, Jupiter perturbs the orbits of nearly 1,000 asteroids to alter their orbits (generally lengthening the semi-major axes) to become Earth-crossing ones. Even in the best of times and (budgetary) circumstances with the most resources we can barely keep track of half the newcomers. Most worrying, limited resources means we have to focus on the larger threats, like Hermes. Thus, "hiding" is the wrong term to use. Also saying we will "know of them eventually" is kind of dense. It isn't much help to us if "eventually" arrives just as a monster asteroid is nearing our atmosphere!
Sulzer then brought down the wrath of the other poster (who knew about asteroids) on himself directly, when a problem to do with Jupiter's perturbation of Earth's motion was posed to Sulzer. The original asteroid poster then demanded Sulzer complete the problem solution or admit he had no place in the discussion. The problem posed was
We want to quantitatively estimate the affect of Jupiter on the orbital position of Earth. The respective masses are: m1(Sun), m2(Earth) and m3 (Jupiter) and we assign relative radius vectors that approximate to the actual distance in AU or astronomical units where 1 AU = 149 million kilometers. Thus, r = 1.0 and r3 (for Jupiter) = 5. Let D denote the separation between Earth and Jupiter and is the key parameter for estimating the magnitude of the perturbation.
The angle S separating the r and r3 vectors can be anything but for working purposes let's use S = 120 degrees, which yields a value: cos(S) = cos (120) = (- ½.)
Now estimate the perturbation given the first three Legendre polynomials are
Po = 1
P1 = cos (S)
P2 = ½ (3 cos^2(S) – 1)
Which was directly taken from this blog, see, e.g.:
Rather than Sulzer doing the problem, another poster 'internetninjasurfer' did it, at least to the point of computing the perturbative quantity (1/Delta). Obviously frustrated, the original pro-asteroid poster then challenged Sulzer to complete the whole problem which meant working out the actual physical quantity formulation. This Sulzer dodged again, while wading into the murky area of probabilities and challenging the notion that temporal-based probabilities were legit, say like Sir Martin Rees' prediction that the probability is that at least one major asteroid strike will occur in the next 50 years. (See, e.g. Our Final Hour, p. 92).
The pro-asteroid concern poster then hit back with a brilliant riposte, challenging Sulzer to account for the fact that the probability of proton fusion in the Sun's core is given in a temporal format: e.g. one fusion every 14 billion years, for the proton-proton cycle. He then also challenged Sulzer to explain how it is the Sun is shining if the fusion probabiity is so very low.
Evidently, Sulzer dodged this too, while a quick and dirty bit of research would have shown him that the extreme low incidence of single fusion per proton pair, is balanced by the vast numbers of protons in the core (over 35 trillion). Hence, these vast numbers compensate for the single pair probability and increase the temporal occurrence rate radically. We also can factor in quantum tunnelling, whereby the penetration of the Coulomb (repulsion) barrier is made possible by the proton's de Broglie wave character. Thus, a lower energy particle can penetrate a higher energy barrier.
Note that tunnelling is a general feature of low mass systems, such as single proton (H+) states.
Consider a deBroglie wave arising from (p+) of form: U(x) ~ sin(kx) where x is the linear dimension along discplacement and k, the wave number vector (k= 2π/lambda).
Now, though the associated energy K < V (the barrier "height") the wavefunction is *non-zero* within the barrier, e.g.
So, visualizing axes for this:
! ! !
! ! !
with the "barrier" at height V, we visualize the particle on the left side (o) "tunneling" over to the right side where it has wave function, U(x) ~sin (kx + φ), where φ denotes a phase angle.
Note that if the barrier is not too much higher than the incident energy, and if the mass is small, then tunnelling is significant.
Sulzer was unable to work any of this out, or explain the temporal probability basis. Worse, the pro-asteroid poster administered the final humiliation by posting the perturbation solution:
J' = k^2 m3[ 1/D – r r3/ r3^3] = k^2 m3[…Legendre terms in summation…]
k= [n^2 a^3/ (m1 + m2)]^ ½
n = 2 pi/ (365.2563835 mean solar days)
(n=mean motion of Earth)
a = 1.000000230 A.U.
(Standard astronomical unit)
Then rubbed it in by defying Sulzer to at least give the units for the quantity J' above, which last I checked, he hasn't done up to now.
Moral of the story? It might be wiser to leave out commenting on issues you only think you are familiar with, and especially challenging folks who definitely know what they're about!