Volcanoes seem to be a common topic these days. Yesterday Nautilus published a great piece by Aatish Bhatia on the 1883 eruption of Krakatoa, which tore the island apart and unleashed a sound so loud it was heard more than 4800 km away:
The British ship Norham Castle was 40 miles from Krakatoa at the time of the explosion. The ship’s captain wrote in his log, “So violent are the explosions that the ear-drums of over half my crew have been shattered. My last thoughts are with my dear wife. I am convinced that the Day of Judgement has come.”
In general, sounds are caused not by the end of the world but by fluctuations in air pressure. A barometer at the Batavia gasworks (100 miles away from Krakatoa) registered the ensuing spike in pressure at over 2.5 inches of mercury1,2. That converts to over 172 decibels of sound pressure, an unimaginably loud noise. To put that in context, if you were operating a jackhammer you’d be subject to about 100 decibels. The human threshold for pain is near 130 decibels, and if you had the misfortune of standing next to a jet engine, you’d experience a 150 decibel sound. (A 10 decibel increase is perceived by people as sounding roughly twice as loud.) The Krakatoa explosion registered 172 decibels at 100 miles from the source. This is so astonishingly loud, that it’s inching up against the limits of what we mean by “sound.” #
Those are some mindbogglingly enormous numbers. Aatish does a wonderful job of explaining the science behind an explosion whose effects ricocheted through the atmosphere for days afterward. Check out the full article over at Nautilus. (Image credit: Parker & Coward, via Wikipedia)
this is so real
We see clouds so often that it’s easy to forget how amazing they are. Thankfully German astronaut and geophysicist Alexander Gerst is currently aboard the International Space Station where he often spends his free time taking countless extraordinary photos of the Earth as it’s whizzing by 205 miles below.
Gerst is particularly fond of photographing dramatic shadows cast by cloud formations - something that we cannot see down here on Earth. These stunning photos remind how awesome clouds are as they cast shadows that stretch for thousands of miles across the planet’s surface. Shadows so long that they eventually disappear into the black horizon.
Follow Alexander Gerst’s Twitter feed for new photos shared daily.
Goodnight my beautiful puppy. Wish I could’ve got to say goodbye.
Our solar system officially has eight planets and one star: the Sun. The discovery of an object larger than Pluto in 2005 rekindled the debate over whether such objects, belonging to the Kuiper Belt – a collection of icy bodies located beyond Neptune – should be called planets. Pluto and other large members of the Kuiper Belt are now considered “dwarf planets.”
Planet facts: space-facts.com
Hey look, my tattoo explained finally!