Alex McColgan
speaker
27,837 appearances
101 recordings
1 series
first heard Nov 2024
last heard 11 Sep
Alex McColgan’s voice in public audio — every appearance, attributed to the second.
Trend
recordings per month · last 12 monthsRecordings per month over the last 12 months — 65 in all, peaking in Aug 2026 with 11.
Appearances
Now, let's look a little farther, say at Mars, or the Andromeda Galaxy, or even halfway across the observable universe.
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And still, there is matter made of protons, neutrons, and electrons, as far as the eye can see.
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At first, this might not sound all that surprising.
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But for once, the mystery here isn't that we've seen something we can't explain, but rather that we haven't seen something we were expecting.
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A universe just as full of antimatter.
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I'm Alex McColgan and you're watching Astrum.
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Join me today as we explore the world of antimatter and learn about its interactions with other particles and even with gravity.
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By the end of this video, you'll probably agree that antimatter is a bit weird, but you'll also see why some physicists are frustrated that it isn't weird enough.
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Let's get one thing out of the way first.
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Although it might sound like something straight out of science fiction, antimatter is very real.
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It forms a critical part of the standard model of particle physics, and particles of antimatter have been observed in experiments going back nearly a century.
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The very first detection of antimatter dates back to a 1932 experiment conducted by Carl D. Anderson at Caltech.
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Using a cloud chamber immersed in a magnetic field,
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When charged particles from outer space, broadly called cosmic rays, intercept the Earth's orbit and fly through this chamber, the magnetic field curves their paths according to the charge and mass of each particle, and the clouds show a visible imprint of their resulting trajectories.
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Anderson was hoping this experiment would help determine just what kinds of particles were streaming into the Earth from the cosmos, and he may have found just a little bit more than he bargained for.
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What Anderson saw was that these cosmic rays included both positively and negatively charged particles.
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The masses of the negatively charged particles lined up exactly with the known mass of an electron, but some of the positively charged particles were far too light to be protons.
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Instead, they appeared to have the mass of an electron
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despite having the opposite charge, and so these never-before-seen particles came to be known as anti-electrons, or later, positrons for short.
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In 1936, Anderson would win the Nobel Prize in Physics for this discovery.
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Showing 1521–1540 of 27,837 · page 77 of 1392
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