I love a good mystery. There's something about the phrase "there's something going on here, but we don't know what it is" that immediately makes my ears perk up. And for someone of that bent, there's no field like astrophysics.
The whole science of astrophysics is a relatively new invention. Astronomy, of course, has been around for millennia; there are complex star charts made by Chinese astronomers that date back to the eleventh century, and our observations of the constellations and planets goes back to the time of the Babylonians.
We've been looking up for a long, long time.
The problem, of course, is that looking at the stars from a distance is one thing, but finding out anything about what they actually are when we can't physically go there is quite another. Even finding out what they're made of was a baffling question with no obvious answer. Up until (very) recently, our best telescopes weren't sufficient to see any detail at all on even the largest stars; even through the Mount Wilson Observatory Telescope they just look like points of light with no discernible features whatsoever.
The first step toward seeing more than that came from research by German physicist Joseph von Fraunhofer in the early nineteenth century, when he invented the spectroscope -- basically a very well-made prism -- and found that in the light from the Sun there were dozens of dark lines (now called Fraunhofer lines in his honor). Fraunhofer himself died at the young age of 39 without ever finding out what caused them -- poisoned by vapors from the heavy metals he used in his profession as a glassmaker -- but the research was taken over by Gustav Kirchhoff and Robert Bunsen, who showed that the lines were the absorption spectra of specific elements. Basically, these lines occurred in the light emitted by a heated, glowing gas mixture, and could be used to identify what elements were in the mixture. In fact, it was through its unique spectral fingerprint within the solar spectrum that British astronomer Norman Lockyer discovered the element he christened helium (after Helios, the Greek sun god) -- the first element that was identified out in space before it was detected here on Earth.
What this did was allow us to study the stars at a distance. Their spectra told us for certain what stars thousands of light years away were composed of. Through this new science of astrophysics we found out that most of the ordinary matter in the universe (96%, in fact) is hydrogen and helium; all of the other familiar heavier elements put together make up the other 4%. It also led directly to the discovery of the expanding universe and the Big Bang when astronomer Edwin Hubble found that the familiar spectral lines of hydrogen in distant stars were red-shifted -- stretched out in the same fashion that the sound waves of a passing train get stretched, lowering the pitch as it passes you. And it turns out that unlike trains, galaxies have a peculiar relationship between their distance and their speed. The farther a galaxy is away from us, the more the spectral lines get red-shifted, so the faster it's moving.
The result: the universe is expanding, meaning at one point 13.8 billion years ago, it was coalesced into a single point. All that, from the lines produced when you heat something hot enough to emit light.
Anyhow, all of this comes up because of a new discovery that has the scientists scratching their heads. Astrophysicists Anna Kapinska and Emil Lenc were analyzing images from the Australian Square Kilometre Array Pathfinder (ASKAP) telescope, and found ghostly rings of radio emission that have no known source. Here's one of them, dubbed ORC-1 ("odd radio circle"):
What are you afraid of?
It's a question that resonates with a lot of us. I suffer from chronic anxiety, so what I am afraid of gets magnified a hundredfold in my errant brain -- such as my paralyzing fear of dentists, an unfortunate remnant of a brutal dentist in my childhood, the memories of whom can still make me feel physically ill if I dwell on them. (Luckily, I have good teeth and rarely need serious dental care.) We all have fears, reasonable and unreasonable, and some are bad enough to impact our lives in a major way, enough that psychologists and neuroscientists have put considerable time and effort into learning how to quell (or eradicate) the worst of them.
In her wonderful book Nerve: Adventures in the Science of Fear, journalist Eva Holland looks at the psychology of this most basic of emotions -- what we're afraid of, what is happening in our brains when we feel afraid, and the most recently-developed methods to blunt the edge of incapacitating fears. It's a fascinating look at a part of our own psyches that many of us are reluctant to confront -- but a must-read for anyone who takes the words of the Greek philosopher Pausanias seriously: γνῶθι σεαυτόν (know yourself).
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