Today on Crash Course Astronomy, Phil explains comets. Comets are chunks of ice and rock that orbit the Sun. When they get near the Sun the ice turns into gas, forming the long tail, and also releases dust that forms a different tail. We’ve visited comets up close and found them to be lumpy, with vents on the surface that release the gas as ice sublimates. Eons ago, comets (and asteroids) may have brought a lot of water to Earth -- as well as the ingredients for life.
Check out the Crash Course Astronomy solar system poster here: [ Ссылка ]
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Chapters:
Introduction: Comets 00:00
Comets = Dirty Snowballs 1:19
Comets Have Two Tails 2:52
Short-Term vs Long-Term Comets 4:35
Where do comets come from? 5:06
Comets Up-Close 6:17
What Happens When Comets Hit Earth? 9:15
Review 10:59
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PHOTOS/VIDEOS
Halley's Comet, 1910 [ Ссылка ] [credit: New York Times, Wikimedia Commons]
Bayeux Tapestry [ Ссылка ] [credit: Wikimedia Commons]
Comet McNaught [credit: Phil Plait]
Comet McNaught + tail [ Ссылка ] [credit: Chris North, Wikimedia Commons]
Comet surface [ Ссылка ] [credit: ESA/Rosetta/NAVCAM]
Fine structure in the comet’s jets [ Ссылка ] [credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA]
Comet Halley [ Ссылка ] [credit: Halley Multicolor Camera Team, Giotto Project, ESA]
Comet McNaught [ Ссылка ] [credit: ESO]
Hubble's Last Look at Comet ISON Before Perihelion [ Ссылка ]
[credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)]
Hale-Bopp: The Great Comet of 1997 [ Ссылка ] [credit: Jerry Lodriguss, used with permission]
Sungrazer video [ Ссылка ] [credit: NASA's Goddard Space Flight Center]
“Large Web” graphic [ Ссылка ] [credit: JHUAPL/SwRI/Dan Durda]
Comet Daniel [ Ссылка ] [credit: Max Wolf, Wikimedia Commons]
Vega 1 Low Res [ Ссылка ] [credit: Russian Academy of Sciences]
The Nucleus of Comet Halley [ Ссылка ] [credit: ESA/MPS]
Comet Hartley 2 [ Ссылка ] [credit: NASA/JPL-Caltech/UMD]
Comet 67P/Churyumov-Gerasimenko [ Ссылка ] [credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA]
OSIRIS Catches Activity in the Act [ Ссылка ] [credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA]
Active Pit [ Ссылка ] [credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA]
Depiction of Philae 's planned touchdown on the comet [ Ссылка ]#/media/File:Rosetta%27s_Philae_touchdown.jpg [credit: DLR, CC-BY 3.0, Wikimedia Commons]
Colour Image of a Comet [ Ссылка ] [credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA]
Comet Lovejoy [ Ссылка ]#/media/File:Iss030e015472_Edit.jpg [credit: NASA/Dan Burbank]
NASA’s Stardust [ Ссылка ] [credit: NASA/JPL]
Comet dust [ Ссылка ] [credit: NASA]
Comet Lovejoy [ Ссылка ] [credit: ESO/G. Brammer]
![](https://i.ytimg.com/vi/yB9HHyPpKds/maxresdefault.jpg)