Extraordinary measurements

In the news today is the discovery of a planet about fives times the mass of Earth, orbiting a star 20 000 light years away from Earth.

That’s just amazing. Never mind the implications for the search for life, or any of that — the actual measurement is amazing. A quick back of-the-envelope calculation shows that an equivalent measurement would be observing something the width of a human hair, end on — about 0.05mm thick. It’s not easy seeing that with the naked eye more than about a tenth of a metre away, never mind on the moon.

Meanwhile, the people at LIGO are trying to measure changes in the path length of a ray of light, caused by passing gravitational waves, of less than a thousandth of the width of an atomic nucleus.

And the Large Hadron Collider, under construction near Geneva, will collide thousands or millions of protons a second, and track almost all of the vast numbers of particles each collision creates. We typically talk about atoms in groups of about 10^23 particles, but here we’re talking about tracking each individual particle.

And perhaps most amazing to me, we can make meaningful statements about the whole universe a tiny fraction of a second after the Big Bang, based on a few observations from a single planet in a single place in the universe, at essentially a single point in time in the universe’s evolution.

There are some really smart people out there.

5 thoughts on “Extraordinary measurements

  1. ~600 million (inelastic collisions) per second. not too bad for a theorist 😉

    of course, if you count the number of particles in the beam it is far more exciting! (1.67 * 10^11 per bunch)


  2. Ok, so I under-estimated. Basically, I couldn’t be bothered to look it up. In fact, I’m happiest when you lot just tell me the results. All these numbers are so … practical. Useful even. Uuugh.


  3. Of course, my comment is kind of ironic — I just realised that the whole point of this post was a back-of-the-envelope calculation involving, well, numbers. Oh well.


  4. Wonderful. I was struck by some words of Einstein, referring to the intuitive process of discovering the laws of physics. He talks about these leaps of the imagination arising from intuition, “based upon something like an intellectual love”. and elsewhere, “a sudden illumination, almost a rapture”. It seems that to be a great scientist (rather than just a good one), it may be helpful to cultivate a sense of wonder and excitement about one’s work, to be in love with the sheer awe-inspiring grandeur of it. The modern era has encouraged cynicism and the dismissal of enthusiasm. How sad. Maybe the post-modern era will re-engage with wonder. So thanks for celebrating the extraordinary universe we have the privilege of discovering, the incredible tools that open up these discoveries, and the remarkable people who invent and use the tools. They lift us beyond the ordinary.


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