Three Ways the World Could End
Jan 22, 2011 Jennifer Marsden
The apocalypse has always been the subject of Hollywood intrigue. From asteroid impacts, solar flares, and alien invasion, doomsday has been depicted in a variety of ways since the dawn of cinema. Although many of these films are produced for entertainment value with spectacular special effects, many scientists agree that there is a distinct possibility that one day the world may end in widespread catastrophe. But how will it really happen? There isn't an obvious answer to this question as scientists have come up with a number of scenarios that may put an end to the world.
Meteorite Impact
There is no question that a meteorite will hit Earth, they hit us on a regular basis and are mostly small enough to go unnoticed, but there are exceptions to this. On June 30th 1908 a comet fragment weighing around 100,000 tonnescrashed into the atmosphere and exploded over the desolate Tunguska region of Siberia, Russia, with nearly 1,000 times the energy of the atomic bomb dropped on Hiroshima. The blast from this explosion felled millions of trees. In this instance, no one was injured due to the remote location of the impact. If this impact had occurred in a populated region, it is likely that hundreds of thousands of people would have been killed.
But what are the chances of a similar level impact occurring again? Chris Herd, an assistant professor at the University of Alberta's department of earth and atmospheric sciences agrees that a giant meteorite almost 10 kilometres wide was responsible for ending the age of the dinosaurs. Nevertheless Herd states that "something that big only happens every tens of millions of years… It's possible, but only remotely" that this will happen again (Science Daily, 2008).
Astronomers now estimate that there are around 2,000 Earth-crossing asteroids at least a kilometre across, which could theoretically hit us. An impact of a one-kilometre asteroid could wipe out one quarter of the world's population.
Super Volcano Eruption
A supervolcano is a volcano capable of producing excptionally large eruptions which are thousands of times greater than most volcanic eruptions. At present, six super volcanoes are know to exist: Yellowstone, United states; Long Valley, United States; Valles Caldera, United States; Lake Toba, Indonesia; Taupo Volcano, New Zealand; and Aira Caldera, Japan (Armaggedon online, 2007).
The last known explosion of a super volcano was Toba in Indonesia which erupted about 74,000 years ago. According to USGS, pyroclastic flows covered an area of at least 20,000 square kilometres, with deposits as thick as 600 metres near the vents. Ash darkened the sky all around the planet and worlwide temperatures plummeted by up to 21 degrees at higher latitudes accorrding to Michael Rampino, a biologist and geologist at New York University as quoted in Live Science (2005). Rampino estimated that three-quarters of the plant species in the Northern Hemisphere perished.
The direct impact of such an eruption would result in millions of human deaths in the surrounding areas. The evidence is that past eruptions have wiped out all life within a couple hundred kilometers of the event. In a worse case scenario, an eruption of a super volcano could result in ice covering almost all of Canada, Europe and Northern Asia, for thousands of years. If that were to occur, life would be restricted to a narrow band in the tropics.
Expanding Sun
The Sun is already about 5 billion years and is expected to have a lifespan of about 10 billion years. Towards the end of its life, the hydrogen in the Sun's core will be mostly exhausted. This will instigate a number of chain reactions which will lead the Sun becoming a 'red giant'. As a red giant, the Sun will expand to such an extent that it may possibly consume all of the inner planets including Earth, however we can't confidently consign Earth to the bonfire as of yet.
There is a possibility that the Earth will survive the expansion of the Sun. According to Boris Gaensicke of the University of Warwick, the fate of the Earth is unclear. The planet could be engulfed, or it may narrowly escape as its orbit moves further out (Cosmos Magazine, 2006).
Unfortunately, even if the Earth is not consumed, oceans and most of its atmosphere will evaporate due to extreme temperatures. This is certain to eradicate life from the planet.
Sources
Appell, David. Scientific American, 2008 "The Sun will Eventually Engulf the Earth – Maybe" scientificamerican.com/article.cfm?id=the-sun-will-eventually-engulf-earth-maybe, Accessed on November 12th 2010
Armageddon Online 2007. "Where are there Super Volcanoes?" armageddononline.org/known-super-volcanoes.html, Accessed November 1st 2010.
Britt, R Live Science 2005 "Super Volcano Will Challenge Civilization, Geologists Warn" livescience.com/environment/050308_super_volcano.html, Accessed on November 1st 2010.
Cartwright, John. Physics World, 2007 "Earth Could Survive a Red Giant Sun" physicsworld.com/cws/article/news/31123, Accessed on November 14th 2010
Hawksett, Dave. Astronomy Education "Tunguska Incident" astronomy-education.com/index.php?page=135, Accessed on October 19th 2010
Jones, Hilary. Cosmos Magazine, 2006 "Clues to the Death of our Solar System" cosmosmagazine.com/news/952/clues-death-our-solar-system, Accessed on November 12th 2010
Science Daily, 2008. "More Meteorites May Hit Earth Than Supposed: New Tool Gives A Recount" sciencedaily.com/releases/2008/11/081125141600.htm, Accessed on 1st November 2010
USGS, 2005 "Supersized Eruptions are all the Rage!" usgs.gov/volcanowatch/2005/05_04_28.html Accessed on November 3rd 2010
--
Got Penguins?
Penguin News Today
The Science of Penguins
The Gentoos are back! Come see them on live cam at:
Gentoo Penguins of Gars O'Higgins Station, Antarctica
__._,_.___
No comments:
Post a Comment