Wild gravity

I like to think of myself as scientifically literate, so I’d always been a bit embarrassed that my knowledge of General Relativity was rather superficial. High school physics classes and popular science books had taught me that e=mc2, that gravity is caused by matter warping spacetime, and that clocks slow down when you travel at the speed of light, but until recently I’d have been pushed to explain exactly why these things were so.

Then, towards the end of last year, I watched the movie Interstellar, the plot of which turns on the time-stretching effects of extreme gravitation, which inspired me to fill in this gap in my education. So I’ve read various textbooks, and Einstein’s own pamphlet on the subject, and while, if I’m honest, the mathematics are still a bit opaque to me, I think I’ve got a fairly good grasp of the basic principles.

Just in time too; the day after I finished the Einstein book, the gravitational waves he predicted were finally discovered (or the discovery was announced, the actual event having taken place last year). It’s nice to feel that one understands the importance of scientific advances like this, but even in a state of relative ignorance it would be hard not to be awed by a story that involves black holes spiralling at near the speed of light before crashing to release the energy of a billion trillion stars in the blink of an eye. The fact that we can hear the echo of this cataclysm a billion years later is nothing short of amazing. Despite all the evidence to the contrary, humans are pretty smart.

Total eclipse of the blog

I did manage to catch a glimpse of the partial solar eclipse last week, as the thick grey cloud that habitually blankets the sky at this time of year briefly parted. Though my view of it only lasted a few seconds it was quite impressive, a reminder of the eternal procession of the celestial host.

Except of course it’s not eternal. In about six billion years, the sun, the moon and the earth will all be gone, along with every trace of humanity and its works.

When you think about cosmic time scales like that, a month between blog posts doesn’t seem so bad…

Lunar Requiem

Back in 2009 we ran a piece marking the 40th anniversary of the first moon landing, which noted wistfully that the vision of widespread space travel promised by the Apollo program had never been realised. We returned to this theme on the 50th anniversary of Yuri Gagarin’s maiden space flight, by which time our regret had expanded to cover the passing of the whole concept of progress through rational planning.

The news that Neil Armstrong has passed away is another reminder of how much the world has moved on since the days when flying to the moon was the peak of human aspiration. In a few more years an era in which there exist living men who have walked on another celestial body will have passed completely, with no sign that it will ever be repeated, a thought which I find almost unbearably sad.

Of course the Space Race of the 50s and 60s was driven by Cold War tensions, and it’s hard to argue that the threat of global thermonuclear destruction that hung over that period was a price worth paying for the dreams of space exploration. Nevertheless, I think our culture has lost something important since then; the sense that we could go ever onward and upward, replaced by the generally gloomy feeling that our best days as a species are already behind us.

All hope is not lost though; we’re still sending robots to other planets, and the information they send back may inspire another wave of space enthusiasm. I might yet make it to Mars after all…