Exoplanets: Crash Course Astronomy #27

Today Phil explains that YES, there are other planets out there and astronomers have a lot of methods for detecting them. Nearly 2000 have been found so far. The most successful method is using transits, where a planet physically passes in front of its parent star, producing a measurable dip in the star’s light. Another is measuring the Doppler shift in a star’s light due to reflexive motion as the planet orbits. Exoplanets appear to orbit nearly every kind of star, and we’ve even found planets that are the same size as Earth. We think there may be many billions of Earth-like planets in our galaxy.

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Chapters:
Introduction: Exoplanets 00:00
Reflexive Motion 1:29
Discovering the First Exoplanets 2:07
51 Pegasi b 3:08
Exoplanets in Transit 5:42
Detecting Exoplanet Transits 6:32
Photographing Exoplanets 7:12
Kinds of Exoplanets 8:18
Earth-like Exoplanets 9:33
Review 10:48
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Want to find Crash Course elsewhere on the internet?

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PHOTOS/VIDEOS

[CanuckMonkey]

I love how the script is future-proofed by having Phil say "in 2015" and not "earlier this year" or something. Just one way that this series will be useful for years to come!

[BintBandora]

I always get the chills when I watch these because I is awesome!

[dzarko]

That "one giant leap" quote at the intro gives me chills every time.

[crashcourse]

Yes, this is the episode that went up last week. We pulled it due to a significant error (re: reflexive motion) and are reuploading it today, corrected. Sorry for any confusion!

[Siegetower]

I took my young daughter outside the other night and asked her to count the stars she could see. In the obstinate way only a toddler can answer she looked up briefly and said "5". No amount of suggestions could change her answer. She then sang "Twinkle twinkle little star". She is awesome.

I just had to share with the world.

[MrWolynski]

This needs to be updated to account for the new discoveries.

[IstasPumaNevada]

Exoplanet discovery/research is in my opinion one of the most exciting scientific pursuits of today.

[MrSeekerOfPeace]

6:01 I love learning about transits. The way they did them in the 19th century required expeditions to high points on the earth in which only two or three were successful in capturing the transit in Australia & Japan.

[Kaalyn_HOW]

**doesn't even bother with the comment section this time since 95% is some version of "didn't we already see this?", and me facepalming at the unwillingness to READ**

[cortster]

I have never seen the Milky Way... Stupid light pollution.

[educasanova]

First: Déja vu
Then: Oh, it's a reupload..
Later: I love how every detail of this series is so well treated, thanks!!

[Kazuma]

I love this entire youtube channel so much. But this course has been my favorite by a large margin. Every episode makes me feel so inspired. Thank you!

[trioct]

I'm pretty sure that the error they made is at 1:43. I believe the animation before had the star orbiting with the planet rather than on the opposite side of its orbit.
It's a reminder that scientists will almost always try to correct themselves. ;)

[trwq]

Ok, basically astronomers are really really fucking smart

[effdpaul]

It's amazing that we have the technology to measure such small variations in light intensity and wavelength.

[MrJackOfAllTraits]

I just.... I just so desperately want to live in a time when we become an interplanetary species. So so so bad. *sigh* but I'm sure that wont happen for 10s of thousands of years maybe more.

[SittingGuy]

Hey kid








You're an amazing human being, have an AWESOME day
I also sit on things

[JWK]

I really enjoy hearing about how astronomers figure out things like exoplanet size and mass. It's really interesting to hear the clever ways people have come up with to measure things that can't be seen directly.

[politicallycorrectredskin]

I can remember arguing with a teacher about this once. It made sense to me that if suns are common, planets must be as well. Just because we can't see them doesn't mean it doesn't make endless sense for them to be there. All stars are formed in roughly the same way, so the features of solar systems should be similar as well. Which means that there should be far more planets than stars and far more moons than planets. Because they are smaller and take less matter to form.

[insanitycubed]

Dale Frail has to be one of the coolest scientist names.