00:00We're talking about exoplanets, planets around other stars.
00:03Note that this is an idea that came from Giordano Bruno,
00:07who said, following other scholars, even among the ancient Greeks,
00:10that the stars in the sky are distant suns.
00:13Since our sun has planets, then those stars would also have planets,
00:17which we call exoplanets.
00:20In the meantime, we have telescopes,
00:23but don't imagine that it's very easy to see these exoplanets with telescopes,
00:27because telescopes don't have a very high magnification power.
00:30I'm going to make a video soon about quantum telescopes,
00:33and there might be a revolution there.
00:35Until then, our telescopes, even the space ones,
00:39can only magnify nearby stars.
00:43And so we can't detect exoplanets just by magnifying the images of stars.
00:50Here's our approach.
00:51We use two methods, the transit and Doppler methods.
00:53That's why we're talking.
00:55Today, we're talking about the transit method,
00:57which is used when the planet, the exoplanet,
01:00orbits around the star and passes in front of the star.
01:04So, it slightly occults the star,
01:06and the intensity of the light from the star
01:08suddenly drops for a period of time,
01:10as long as the planet is occulting the star.
01:13And you can see this in this graph from Physica Povestita.
01:17The same method was used for this exoplanet as well.
01:20You can see the measurement here.
01:23It's crucial to understand key points from these measurements.
01:27First of all, we can measure the orbital period of the exoplanet around the star.
01:34Why?
01:35Because we have one event,
01:36and then we'll have another event after some time,
01:39and then another event,
01:40because each time the exoplanet passes in front of the star.
01:44Importantly, we can also measure the exoplanet's size.
01:48Because the larger the exoplanet is,
01:50the more light it blocks.
01:52And the ratio between how much light is blocked
01:56and the total intensity of the light.
02:00It's actually given by the area of the planet
02:02and the area of the star,
02:04and with that, we can find out the area of the planet.
02:06Well, you might ask me,
02:07wait a minute,
02:08but how do you know the area of the star?
02:10Well, you might ask me if I'm going to go to the star.
02:13Well, you might ask me if I'm going to go to the star.
02:15Well, you might ask me if I'm going to go to the star.
02:16Well, you might ask me if I'm going to go to the star.
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