News that asteroid “2018 VP1“, will pass within about 480 kms of Earth on November 2, 2020, has raised social media hopes that it might be drawn in by the planet’s gravity and crash on the White House, thus ending any speculation about the reviled Donald “Putin’s Puppet” Trump’s re-election. However, if you are among the alleged millions who wish for this scenario, I suggest you are being overly optimistic. Not only is the targetting rather too specific, but the chances of it even reaching the ground are very slim. And besides, it’s pretty damned small for an asteroid.
2018 VP1 is about 2m wide. As pointed out in the above-linked article, back in 2013 a much larger (20m) chunk of rock entered the atmosphere over Chelyabinsk, Russia, but exploded before it reached the surface. This rock was dubbed a “superbolide” (a bolide is a large meteor which explodes in the atmosphere): the entry and the heat from the friction caused it to explode about 30 km above the surface. Even at that distance the explosion caused extensive damage to buildings and the landscape. 2018 VP1 is a tenth the size.
In 1908, one of the most famous bolides exploded over Siberia in a similar fashion, causing much greater damage: it’s known today as the Tunguska Event. the rock that entered the atmosphere has been estimated to be about 100m in diameter, and exploded between five and 10 kms above the surface.
So at 2m, 2018 VP1 probably won’t even get that far before burning up or possibly exploding in the stratosphere. Damn, say a lot of Democrats.
But it’s not the only near-earth object (NEO) being tracked. The JPL has a database of known NEOs (pay attention: known. The Chelyabinsk meteor wasn’t spotted until it was almost right on top of Siberia, in part because it came from the sun side so was hidden in the sun’s brilliance). There are a lot of rocks in space, enough to conjugate a whole Donald Rumfeld “known unknowns” speech.
The JPL database distances are measures in lunar distance (LD) or astronomical units. I assume readers already know what these are and don’t need my pedantic explanations. Still, have your calculators ready when you check the site because it’s written for astro-nerds and Trekkies. And keep in mind that the orbits of these rocks are a best-guess situation, which is why a projected maximum and minimum distance are listed.
On Sept. 1, 2020, 2011 ES4 will pass within 0.32 LD (0.00081 AU) of the Earth at its maximum, but only 0.19 LD (0.00048 AU) minimum. Close by stellar standards, but not particularly close by local measurements: 121,174 kms away. Or roughly one third of the distance From the Earth to the Moon (gee, what a great title for a book…). At between 22 and 50m in diameter, it could make a big bang if it hit (albeit not nearly the bang that happened with the asteroid that killed the dinosaurs). But that is an unlikely prospect.
(Sorry for those of you who still use the archaic imperial system: metric is simply so much more sophisticated and logical that using imperial today is like speaking in Chaucerian English).
2018 VP1 is a bit harder to best-guess, it seems, probably because it’s so small and small items are more subject to the vagaries of gravity. At it’s closest it is predicted to come 0.02 LD (3.91e-5 AU) or about 7,700 kms away. At its furthest, it will swing way past us at 1.09 LD (0.00280 AU), or well outside the Moon’s orbit. So that’s a big no for those of you who hoped it would crash land on Trump’s desk.
So why does the news report say 480 kms (well, it actually says 300 miles, but that’s such an old-fashioned affectation, I won’t indulge it…)? Because the distances in the NEO database are from the CENTRE of the planet, not the surface. So when you subtract the radius of the planet (about 6,334 kms) from the closest approach, 2018 VP1 suddenly looms a lot closer. But with my math (subtracting 6334 from 7,700, I get the rock whizzing by us around 1, 354 kms away. Maybe I calculated wrong.)
By astronomical standards, that’s a hair’s breadth. But still a helluva long way away: greater than the driving distance from Toronto to Halifax, and almost as far from Toronto to Winnipeg. I don’t think we have a lot to worry about. Even the ISS is a lot closer to Earth, at approx. 3509-410 kms above us. So the rock will pass far, far above them.
Anyway, 2018 VP1 is neither a cause for concern nor for hope. As Forbes magazine tells us:
…there’s not really much reason for concern. For one, there is still very high uncertainty around how close this space rock will actually get to our planet. According to NASA’s close approach database, it’s expected to come as close as 4,700 miles or maybe more like 260,000 miles. That’s quite the range.
So forget the bolide as your deus ex machina: the only way to oust Putin’s Puppet from the White house will be to vote him out. And I’m sure you’re all up to the task. After all, your democracy, your future, your very survical depends on it.