Posted in Science & Nature

Shooting Star

When an object from outer space enters the Earth’s atmosphere, it starts to burn up and creates a brilliant streak in the sky, which we call a meteor or shooting star. Contrary to popular belief, this is not due to friction with the air in the atmosphere.

An object entering the atmosphere is typically travelling at extraordinary speeds. Most meteors are travelling around 20km/s (or 72000km/h) when they hit the atmosphere. At these speeds, air molecules do not have a chance to move out of the way. The meteor will instead collide into the air molecules, pushing them closer and closer to each other, compressing the air in front of it.

As we know from physics class, compression increases temperature in gases as per the ideal gas law (PV=nRT). The impressive entry speed of these meteors result in so much air compression that their surface can heat up to 1650 degrees Celsius.

The heat boils and breaks apart the contents of the meteor, turning it into superheated plasma that gives off a glow. This is the streak of light that we see in the night sky when we wish upon a shooting star.

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Posted in Science & Nature

Verneshot

If there is one thing we learn about dinosaurs, it is that they were wiped off the face of the Earth by an asteroid impact. Another feasible theory is that a supervolcano eruption completely destroyed the ecosystem, wiping out all life on Earth by either directly destroying them via a massive shockwave (if they were within range), or by slowly starving them as the resultant plumes of smoke would have blotted out the sun for years. But interestingly, scientists looking back over some extinction-level events of the past, discovered signs of both an asteroid strike and a volcanic eruption. This sounds to be extremely implausible, as the odds of both happening in the same era are near impossible (unless there is some extremely vengeful deity that hated the dinosaurs).

One theory that tries to explain all of this is the verneshot theory. To better understand the concept of a verneshot, imagine a cartoon character such as Yosemite Sam (the beloved red-bearded, gunslinging cowboy character on Looney Toons) shooting his gun wildly into the sky. Cartoon logic dictates that his bullets will eventually fall back on some unwary bystander. Now imagine if the Earth did the same thing, but instead of a bullet it shoots a giant piece of rock capable of causing mass extinction into the sky.

A verneshot occurs in a similar way a supervolcano erupts, where there is an incredible build-up of super hot molten rock. A supervolcano would be when this molten rock erupts as lava. In the case of a verneshot, massive amounts of carbon dioxide build up instead, leading to a pressure build-up under the crust. When the pressure becomes too much, the crust explodes, with the piece (of indeterminate size) being rocketed into space. However, the giant rock does not end up in space. Instead, it is only launched to a sub-orbital altitude, meaning it will come crashing back down to Earth due to gravity. Thus, a verneshot is when a volcanic eruption acts as a giant cannon to launch a piece of the Earth into the sky, which falls back to Earth as an asteroid-like object.

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Posted in Science & Nature

History Of The Earth

The Earth has been around for a good 4.6 billion years. Let us compress the long time from the Earth’s birth to today (2012) into one year to put everything in perspective.

The Earth’s history starts on January 1, 00:00:00. The Earth is a hard sphere, barren as any other planet. Incessant wind and rain erode away the barren mountains and tectonic forces create new ones. Nothing much happens for the next three months. Then, around the start of April, life begins in the form of bacteria. Over the course of the next few months, the bacteria divide and mutate, slowly forming new life forms that are multicellular. However, all life on Earth are still in the oceans.

Life on land only starts in the end of November, when plants begin to settle on land. Plants expertly take the abundant carbon dioxide in the atmosphere and convert it into oxygen. By early December, the oceans are teeming with fish, some of which adapt to living on land by developing lungs. These become the first amphibians. Insects also populate the land and become one of the most diverse types of life.

In December 12, reptiles evolve and the land is ruled by dinosaurs, but only for 9 days until they are wiped off the face of the Earth by a meteorite on December 20. Mammals quickly take the niche left by dinosaurs, populating the entire world. Even at this late time, there are no signs of humans.

December 31, humans have still not arrived on Earth. They only appear around 8pm, where the first hominids venture on to the plains of Africa. At 10pm, the Ice Age begins and the Earth is covered by a thick white sheet of ice. The ice comes and goes three more times. At 11:59pm, human civilisation begins as cities begin to rise. 22 seconds before the end of the year, the Egyptians build their pyramids. More monuments arise within seconds. At 11:59:47pm, Jesus teaches the people to love one another, until he is killed a millisecond later. In the last second of the year (about 150 years), humanity: has two major world wars, take to the skies, create the nuclear bomb that can wipe out all life on Earth and even step foot on the Moon.

We may like to think that we have made a significant impact in the history of the Earth, but we have only existed for an infinitesimally small fraction of the history. We are but a dot on the grand scheme of natural history.

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Posted in Science & Nature

Badass Weapons Of Nature: Mantis Shrimp

In April 1998, a shrimp by the name of Tyson punched through the quarter-inch-thick glass of his cell and attempted an escape. He was promptly caught and had to be sent to a more secure facility. Unlike his boxing counterpart, Tyson was merely 10 centimetres in length.
Mantis shrimp are well-known for their “fists of fury” – officially the fastest punch in the natural world.

Their weapons of choice are their clubs that can be retracted and folded under their head. Using a remarkable energy-storage system – much like the cocking mechanism of a gun combined with a spring – the mantis shrimp can unleash its rounded, stubby claws at a speed of 80km/h to hit its target in 0.003 seconds. This is an amazing feat given that it happens underwater, where the water puts up a significantly higher resistance compared to air. The acceleration needed to produce this awesome punch is 10,000 times the force of gravity (similar to a bullet). In simpler words, researchers could not film using high-speed cameras and needed to borrow a super high-speed camera just to see the punch happen. 

However, the surprises do not end here. Researchers soon found that each strike by the mantis shrimp not only inflicted heavy physical damage, but the sheer speed of the punch created cavitation (implosion of bubbles). Much like the pistol shrimp, this cavitation releases massive amounts of light and heat energy. This shockwave happens immediately after the punch, essentially resulting in the target receiving a deadly one-two hit combo which instantly knocks it out (or disintegrated). 

The force of the mantis shrimp’s punch can easily penetrate the hard shell of most crustaceans in the ocean, meaning no creature is safe. Mantis shrimps have also been observed beating up fish and octopi – and succeeding.

Not only does the mantis shrimp have the most powerful strike, it also has one of the most sophisticated eyes in nature and is extremely agile. This, combined with the shrimp’s cunning nature makes it the perfect hunter. It tends to ambush prey and swiftly knocks it out before it knows what hit it. If the one-hit KO fails, the mantis shrimp uses its agility to hit the foe and quickly swim away, then hit again from the other side until the foe is crushed.

Lastly, the shrimp described above is actually one type of mantis shrimp called a smasher. There is another subtype called spearer with claws modified into sharp spears that can be thrusted with the same force as the smasher’s clubs.

The only adequate metaphor to describe this awesome creature would be a Mike Tyson punching as hard as he can, in his prime, while his fist is attached to a meteor entering the atmosphere.

(Image source: Cracked.com)

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