‘Rubbish, absolute rubbish’
The end is nigh, the self-proclaimed prophets of doom are shouting from the rooftops, sending chills down the spine of gullible men, women and children.
They have even set a date with destiny for all and sundry — December 21, 2012. The tales of alleged horror spreading not only mouth-to-mouth but also on e-mail include that the world will end in December citing the abrupt conclusion of the Mayan calendar, ‘three days of darkness’ in the wake of storms playing havoc on the Sun’s surface that would disable power grids and the Earth’s magnetic field being turned turtle by a galactic alignment.
The most-recent tale of mass death and destruction, doom and gloom, to send fear into the hearts of people is that the world will be engulfed in darkness for three long days on December 22, 23 and 24, the Sunday Times gathers from many who have heard it. There will be no electricity, they have been told, and people will be able to light only certain types of candles that have been blessed.
“Stay in your homes, shutting and barring all doors and windows, for evil will roam outside and will attempt to enter homes in the guise of pleading voices of close kith and kin. Don’t open your doors for if you do, disaster will strike,” is what is being touted among the faint of heart.
“Rubbish, absolute rubbish,” is how a veteran scientist responds when asked for comments by the Sunday Times.
The “three days of darkness” is religious paranoia, having the same foundations of religious belief, says Astrophysicist Dr. Kavan Ratnatunga, stressing that it is like accepting something on faith because science is not understood.
The President of the Astronomical Association of Lanka, Dr. Ratnatunga comes with indisputable credentials to make expert comments on situations like this. Calling himself the “only” astrophysicist currently in Sri Lanka, he not only has a doctorate in the field but has also done post-doctoral research at America’s Institute of Advanced Study, Princeton — where none other than Albert Einstein of Theory of Relativity fame himself had spent his last few years; the Goddard Space Flight Center, Greenbelt; Johns Hopkins University, Baltimore; Carnegie Mellon University, Pittsburgh; and the Dominion Astrophysical Observatory, Victoria, Canada to name a few.
Before getting to the crux of the matter, he points out that faith convinces many people of things which are not accurate. There have been instances where astrologers have predicted that they may die on a certain day, and in fact they have died on that day.
This is not because astrology is true but they have died because of pure fright, says rationalist Dr. Ratnatunga, dispelling the doomsday rumours as “dangerous things” not based on any scientific reality. Dealing specifically with the four factors that could destroy life on earth, he says they are an asteroid or space rock strike, gamma-ray bursts, a supernova or flipping of the earth’s magnetic field.
Picking out the asteroid strike, Dr. Ratnatunga says that for such a strike to destroy a significant amount of life on earth, the asteroid would have to be more than a few kilometres in diameter. Such an event would usually occur once in 25 million to 100 million years, he says citing an occasion when such a strike is known to have taken place. “Sixty-five million years ago, a 4-6 km asteroid struck near the Yucatan peninsula, Mexico, and killed off all the dinosaurs.”
Looking at the bright side for humans in the extinction of the dinosaurs, he travels back in time to paint a picture when these gigantic reptiles dominated the world, not allowing mammals to evolve. The elimination of the dinosaurs paved the way for the mammals, starting with the shrew, and led to the evolution of humans.
According to him the US National Aeronautical Space Agency (NASA) Spaceguard programme is locating asteroids and will soon have a 90% complete catalogue of all asteroids more than 140 metres in diameter crossing Earth’s orbit.
We now have the techniques to divert any asteroid heading towards earth if we have a few years’ warning, says Dr. Ratnatunga.
Moving to gamma-ray bursts, this scientist says these powerful explosions of energy in the cosmos are detected from external galaxies every day. Among the many theories about what triggers them, the most popular is that two ultra-dense neutron stars collide giving forth a huge burst of gamma rays seen all over the universe. “This happens in a particular galaxy once in about 500 million years and is assumed to have been instrumental in wiping out about 90% of species 450 million years ago and may be also 250 million years ago, causing two major extinctions of numerous species on Earth.”
But, he once again shows the light at the end of the tunnel — even then, all of life on earth didn’t die.
If a gamma-ray burst does occur in our galaxy, the Milky Way, “we’ll be fried”, with a lot of life on Earth getting destroyed, he says, hastening to add, however, that such bursts are extremely rare.
The third possibility, according to this star-gazer, is a supernova – the explosion that occurs at the end of the life of a massive star– if it happens within 30 light years from us. On average, they happen only two per century in the Milky Way which is 100,000 light years across, says Dr. Ratnatunga, giving a basic physics lesson to the uninitiated.
Referring to measurements of distance using the speed of light, he says, the Sun is eight light minutes away from Earth, while our Solar System is several light hours across. The star closest to our Sun is 4˝ light years away. Astronomers have catalogued all the stars within 30 light years and know that none of them is in the process of becoming a supernova within the predictable future.
Finally, Dr. Ratnatunga deals with the flipping of the earth’s magnetic field which occurs on average every 250,000 years. Although it last happened 640,000 years ago, there is no regular or timed cyclic occurrence, he says, adding that sometimes there is no magnetic field flip in 40 million years.
“It is random and there are no indications that it will occur in December 2012,” he says, explaining that although the magnetic field is currently down at a rate of 0.1% per year, but as it is known to fluctuate over long periods, it is unlikely to become zero and turnaround even in a thousand years. During the time of a flip, there will be no protection from the Van Allen belt (a cocoon surrounding the Earth, except at the magnetic poles, at heights of several tens of thousands of kilometres that trap radiation). Radiation from the Sun will beat down powerfully due to the weak magnetic field until it becomes stronger.
However, there will be no major catastrophe and decimation of the Earth’s population, only an increase in diseases such as skin cancer.
Pinpointing the greater threat that is global warming, Dr. Ratnatunga explains that between 14,000 to 7,000 years ago, the sea level rose 120 metres to what it is today, due to the melting of the ice locked up during the Ice Age.
When the floating ice in the Arctic melts, it does not cause a sea-level rise as an equal volume has already been displaced. However, when ice on land, like that which is on Greenland melts, if the Earth’s temperature goes up by 2°, the sea level will go up by 7 metres. If due to global warming the temperature increases by 6° the sea level will go up by 73 metres after all the permanent ice on Antarctica melts.
Although it will take a few thousand years, Dr. Ratnatunga’s passionate plea is to put the world’s resources into efforts to stymie global warming.
Putting time in perspective in no uncertain terms, Dr. Ratnatunga says our civilization is only about 5,000 years whereas the universe is 13.7 billion years old. If we equate the age of the universe to one cosmic year of 31.5 million seconds, each cosmic second is 434 years.
When one looks at it from that perspective, our civilization has been around only for a mere 10 cosmic seconds. The human race (Homo sapiens) has been around for about 200,000 years which works out to just eight minutes of the cosmic years. “So we mustn’t worry too much,” he adds, leaving the reality about life uttered by William Shakespeare in ‘Macbeth’ resonant even now……..
“Life’s but a walking shadow, a poor player,
That struts and frets his hour upon the stage
And then is heard no more: it is a tale
Told by an idiot, full of sound and fury,
Only predictable disaster– many, many thousands of years away
The nearest and most-predictable disaster is a super-volcano, says Dr. Ratnatunga, and the one set to erupt is at Yellowstone in America but that too not tomorrow, day-after or even in 100 years but within the next 50,000 or 100,000 years.
The last super-volcano to erupt was in Toba on the Sumatran island, 74,000 years ago killing off the whole of the Earth’s population except about 10,000 people inclusive of 1,000 mating pairs.
Ending on a lighter note, this astrophysicist walking into the realm of genetics, says that DNA analysis has determined that the whole world’s populations relate to those 1,000 couples. “So all of us have a common ancestry,” he quips.
Cosmic rays: Spreading panic via sms
The frenzied text message sent close to midnight read: “Tonight 12.30 a.m. to 3.30 a.m. cosmo rays entering earth from mars. So switch off your mobile at night. Don’t keep your cell with you & put it away while you are sleeping because they are very dangerous rays. NASA BBC NEWS.”
Debunking the rumours, Dr. Ratnatunga says that the earth is constantly bombarded by cosmic rays every day but is unaffected because of the protective Van Allen belts.
Cosmic rays are not emitted by planets like Mars but only from stars and events like interactions with black holes, the Sunday Times learns.
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