For those of you who missed it last week (and that would be literally everyone), a large asteroid passed by Earth on Tuesday, 18 January at a minimum distance of 1.93 million km (1.2 million miles): not close enough for comfort, precisely, but at more than 5 times the distance of the moon, not exactly cause for alarm either.
The asteroid, discovered in 1994 by Robert McNaught and given the catchy name (7482) 1994 PC1, is roughly 1 km (0.6 mi) across and hurtled past our planet at a zippy 19.56 km/s, or 43,754 mph. Definitely not something I'd want to bump into by mistake! But not to worry, as this is calculated to have been the closest approach for at least the next 200 years.
You can read more about it and watch a video captured by members of the Sociedad de Astronomia del Caribe in Puerto Rico on EarthSky.
Unfortunately things are not going so well for residents of Tonga at the moment, where the largest volcanic eruption in 30 years has led to shortages of drinking water and food, affecting some 84% of the population. The death toll has also sadly increased to 3 since my initial post. Extensive damage across multiple islands continues to hamper relief efforts by interfering with communications systems and access by air and sea. The force of the explosion has been estimated at more than 500 times that of the atomic bomb dropped on Hiroshima in 1945. Ash and particulates from the eruption have blanketed the entire area, leading to extremely unhealthy conditions which will likely persist for some time.
In addition, a number of highly unusual atmospheric effects were observed around the time of the explosion: Gravity waves (not to be confused with the gravitational waves predicted by Einstein's general theory of relativity!) stretching from the surface of the ocean to the ionosphere over a distance of more than 16,000 km and wrapping around the Earth several times produced a set of patterns never before seen by scientists. And according to meteorologist Kevin Hamilton at the University of Hawaii, a phenomenon first predicted by the French mathematician, physicist and astronomer Pierre-Simon de Laplace produced extreme low-frequency perturbations in barometric pressure lasting several minutes across the entire globe. These atmospheric oscillations had been observed previously as a result of nuclear weapons tests and the eruption of Krakatoa in 1883.
Who knew that the entire planet's atmosphere could resonate like an enormous musical instrument, producing a fundamental pitch too low to be detected by the human ear?? Now that's far out!
I wonder how many octaves below middle C that is? Any guesses?
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