Why we wrote 'A Vested Interest'

We on earth face a looming disaster and no one is doing anything about it. On average, every 100,000 years an asteroid or comet hits the earth causing a major extinction. One such extinction happened 65 million years ago and wiped out the dinosaurs. Since then we've been incredibly lucky. History records only small events. One in China in 1490 was reported to have killed 10,000. A remote forest in Siberia was flattened in 1908 and 1,500 were injured by an explosion above the city of Chelyabinsk in Russia. We asssume that because these events are rare that we are safe but that's not the case. Sooner or laterm there will be another impact event as big or even bigger than the one which destroyed the dinosaurs. When it happens we and many other lifeforms on earth face extinction.

So what can we do about this?

Until people face up to the danger, little will happen. People don't see a need. Perhaps that will change in 2029 when on April 13th the asteroid Apophis will pass near earth and pass even nearer in 2036. There's still a slight risk that Apophis could strike earth and a greater risk of it striking the moon in 2036. Aphophis is much smaller than the Everest sized rock which destroyed the dinosaurs so few people apart from some scientists will take notice. There's also a smaller asteroid, 2024 YR4, which has a 4.3% chance of hitting the moon on Dec 22nd 2032.

Without a clear danger nothing will happen. The trouble is that we are unlikely to get any warning at all if the object is an extra-solar visiter such as the one named 'Oumuamua was discovered on October 19, 2017 when it was already heading away from the earth and sun! Until an object strikes a populated area and kills thousands no one will care. An asteroid capable of doing this strikes the earth once a year on average! Most events pass unseen though since more than half of our planet is ocean and large areas of the land are uninhabited.

Things could be a LOT worse though. There are wandering inter-stellar planets, neutron stars and mini black holes which don't even have to strike the earth to kill us. Any of these would create a cosmic game of billiards which could bombard the earth, cause massive earthquakes, tidal waves and eruptions, or even move it out of orbit outsides the 'goldilocks zone' where life on earth can survive.

Impact events are not the only cause of mass extinctions though.There are others:

• Supervolcano eruptions: The earth has a number of supervolcanoes which produce devastating eruptions which cause dramatic climate changes worldwide. Yellowstone in the US is probably the best known. This cause has been proposed for the End Cretaceous, End Permian, End Triassic, and End Jurassic extinctions.
• Magnetic pole recersal: This has happened often in the earth's geological history. When it occurs the earth's magnetic field collapses for a while and there's a dramatic increase in radiation levels. Enough to kill those living on the surface of the planet. Geological evidence shows us that the Earth's magnetic poles reverse every 200,000 years on average. The last one was 700,000 years ago so we would seem long overdue for this.
• Nearby supernova: Again a devastating cause of radiation. A nearby gamma ray burst from a supernova within 6000 light years distance could cause enough radiation on the surface of the Earth to wipe out most of the larger animals including humanity. Astronomers tell us approximately 1 gamma ray burst can be expected every 540 million years. This has been suggested as an explanation for the End Ordovician extinction event.
• Severe solar flare; millions would die from radiation and electrical devices could be destroyed.
• Nuclear war: Apart from the destruction and radiation, a global nuclear war could throw sufficient dust into the atmosphere to cause a nuclear winter which would prevent crops growing for up to two years and bring about mass starvation.
• Solar old age; as the Sun uses up all its hydrogen fuel, helium at it's core will start nuclear fusion causing an increase in solar temperature. The result is a gradual increase in the sun's size. This process will continue until, around 5 billion years from now, the Sun will be 100 million miles across - encompassing the entire orbit of the Earth. Life will have been extinguished on our planet long before that.

There are other possible ways that humans could become extinct without destroying the world:

• Climate change; both hot and cold
• A new disease, possibly man-made and more deadly than Covid-19
• Nanotechnology; while in our books it can be of great assistance in other circumstances it could be worse than a biological plague. This scenario is known as 'the grey death.'
• Superseded by technology; While I prefer to believe that Artificial General Intelligence will develop a superior morality to human morality that might not be the case.
• Resource depletion; imagine a scenario where we run out of metals or fossil fuels. We don't have the resources to find and extract more. We can't obtain them from Space since we don't have a way of getting there. Billions would die and those left would be back to the stone age.