The Fragility and Vulnerability of Human Life within the Universe

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Asteroid 2024 YR4 has been making the news. Most asteroids don’t get much media coverage, but if they have a 2.3% chance of hitting the earth in December 2032, and they are big enough to wipe out a city with an explosion equivalent to an atomic bomb, their story becomes significant. It has even led China’s State Department for Science and Technology to post three job adverts for a team in ‘planetary defence’.

For the next couple of months, this asteroid is close enough to the Earth that its path can be studied by telescopes. Indeed, so important is it that the powerful James Webb Space Telescope will be pointed in its direction. The hope is that more observations will help us to predict its path to narrow down the chances of impact to between zero and twenty per cent.

Of course, such an Armageddon could be easily avoided by sending Bruce Willis into space with a nuclear bomb! The trouble with such a scenario is that blowing the thing apart leads to a multitude of unpredictable rocks hurtling towards us. More realistically, a kinetic impact of spacecraft to knock the asteroid into a safer orbit is possible. In fact in 2022, NASA trialled such a scenario with its Double Asteroid Redirection Test – its DART spacecraft – which crashed into the asteroid Dimorphos at 14,000 miles an hour. The test was successful, showing such a method can work.

While Asteroid 2024 YR4 at between 40-100m in diameter would cause considerable damage to the Earth, it is small compared to the comet which is believed to have led to the mass extinction which included the dinosaurs some 65 million years ago. This comet would have been kilometres across. In the 1980s I worked with Mark Bailey and the then-Astronomer Royal Sir Arnold Wolfendale, looking at how often such a cometary impact might happen. We concluded that such a scenario would only occur on average every 250 million years. The interesting thing about this is that in Earth history, mass extinctions happen every 30 million years or so. Therefore, as well as vulnerability from space, there may be another closer-to-home mechanism that causes extinction, for example enhanced volcanic activity which changes the global temperature of the Earth.

All of this raises some big questions about the future and the place of human beings in the Universe. A small minority of religious commentators have already claimed that the asteroid is fulfilling prophecies of the end times when ‘stars will fall from the skies’. For a number of scientists, the fragility and vulnerability of the Earth to asteroid or cometary collision is part of a motivation to distribute humans to different places. Whether it be Jeff Bezos’s vast orbiting space stations or Elon Musk’s colonisation of Mars, if life on Earth were to be catastrophically ended then the human race would go on. In fact, there are some scientists who are even advocating directed panspermia. They believe that life on Earth is such a one-off in the universe that we have a responsibility to protect it, and part of this would be to send test-tubes of life out into the universe just in case it is all destroyed here.

For the Christian theologian, as well as the politician, there are big questions here. Any scenario — whether it be a DART mission to knock an asteroid off course or the move of humanity into space — would need a collective effort between nations and industry. Who decides on what is best to do, and who pays? These questions are about how we see humanity as a whole rather than national interests or supremacy. Is there a political will and humility to embrace this, or is each country which can afford it vying about who is the best at planetary defence?

Some would argue that such a threat might actually bring the governments of the world together to confront a common enemy. 

And yet the irony of this, is that we have already been staring global catastrophe in the face for some decades, as we have understood in great detail the science and politics of environmental pollution leading to global heating. This emergency has not led to the level of collective action which is necessary and achievable to deal with the threat. Perhaps this is due to a more gradual and diffuse threat than a one-off asteroid, or perhaps it is because caring for the environment is far more costly at both an individual and national level.

The media coverage of Asteroid 2024 YR4 is a reminder of the fragility and vulnerability of human life within the universe. The beauty of the stars comes with a universe of risk. For the Christian, any doctrine of creation must take this into account, as well as the freedom that we have as human agents to value the creation of which we are a part. Valuing life requires collective action, which needs moral commitment, leading to political decisions. Here the moral commitment for me comes not from the fear of extinction, but that God has given us the gift of the Earth, and one day we will be accountable to Him.