There are cosmic threats to life on Earth.Hiding in the depths of space are things lethal beyond imagining.One day the End will be nigh for real.A forthcoming conference, part of the Edinburgh Science Festival, will discuss how the Universe could kill us all.
Hosted in Edinburgh, Science Festival 2011 runs from 9-22 April 2011. At its close on Saturday 23 April, there will be the Cosmic Threats to Earth Public Lecture Event (followed by the End of the World Ceilidh to cheer everyone up). This is a free event (no tickets required) featuring a host of excellent speakers including Prof. John C Brown, Astronomer Royal for Scotland, Lord Rees , Astronomer Royal and Sheffield University’s David Hughes. It looks to be a fantastic opportunity to hear the facts about the threats from above our heads from leading experts, it shouldn’t be missed!
What are these extra-terrestrial menaces?To whet your appetite (and scare your pants off) here are three ways civilisation could end.
1. Asteroid impacts:Everyone is familiar with this idea, once a vaguely heretical idea, the theory that small Solar System bodies can collide with our planet with dramatic consequences has become mainstream science.The theory has pervaded popular culture inspiring both great works of science fiction and also Michael Bay’s 1998 movie Armageddon. There have been several such impacts in Earth’s history. One, not the most devastating, is especially well-known. We know that 65 million years ago an asteroid about 10 km (6 miles) in diameter slammed into what humans later named the Gulf of Mexico. To describe the results as cataclysmic would be to make an understatement. The impact probably caused a tsunami hundreds of metres high. Red hot dust, ash and super-heated steam would have scoured Central America, followed by a global firestorm. Dust and ash blasted into the upper atmosphere blanketed the Earth for years, shrouding the planet in cold and darkness. Poor dinos, they never had a chance. But would we fare any better if it happened again tomorrow?
2. Solar events:The Sun is vital for life.The Sun is a killer.The same star which brings us light and warmth can cause death by thirst, sunstroke or by inducing a slow cancer.Could the Sun be more lethal still?We know it is prone to violent outbursts, known as solar flares.These awesome explosions can throw billions of tonnes of sub-atomic particles travelling at millions of kilometres per hour into interplanetary space.Occasionally one of these onslaughts, a Coronal Mass Ejection, falls on our planet.Luckily for terrestrial life, Earth’s magnetic field shields us from the Sun’s fury (and we may see a beautiful auroral display instead).However a big enough solar eruption could induce a magnetic storm, sending compass needles spinning or inducing damaging surges of current down electricity distribution lines (such an event triggered power cuts across Canada in March 1989:an event 150 million km away deprived five million people of electrical power for days).A really big Coronal Mass Ejection (nothing like this has been recorded) could ruin delicate microprocessors across the planet.Imagine if you woke up tomorrow and there was no TV, radio, cellphones, internet, satnav or computers.It may sound an idyllic dream but I suspect it would be a nasty, brutish and short nightmare.
3. Gamma ray bursts:Imagine an honest to goodness deathray from space surpassing anything the maddest scientist has ever dreamt up.From out of a clear blue sky, death falls across the Earth at the speed of light as a cosmic blowtorch of lethal radiation sterilises our planet of everything from paramecia to people. It may never happen, but it could.Mysterious for decades after their discovery, gamma ray bursts are extremely rare short flashes of astonishingly intense radiation from deepest space.Gamma ray bursts release as much energy in ten seconds or so as the Sun will in its entire lifetime of billions of years.They are the most luminous events in the Universe.As far as we know a gamma ray burst is actually a beam.As the core of a massive star implodes (initiating a supernova explosion), the incredible magnetic forces in the star’s centre focus twin tight beams of intense radiation and matter in opposite direction.These tear their way out of the star and blaze across the Universe. All gamma ray bursts so far observed have been billions of light years away and that is a good thing.A gamma ray burst in the Milky Way would be lethal to life on Earth from thousands of light years away (if the Solar System was lined up with one of the beams).Thankfully astronomers have yet to find any star with the potential to menace Earth in this way.
Astronomy has shown the Universe to be a violent and deadly place.Luckily our world has been a safe and tranquil home through mankind’s reign.It won’t always be so, one day our planet will not dodge a cosmic bullet.I wonder when.