Comets: Crash Course Astronomy #21

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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 in 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.

Table of Contents
Comets Are Chunks of Rock and Ice That Orbit the Sun 1:26
When They Get Near the Sun They Turn Into Gas 2:08
Comets Release Gas Via Vents As Ice Sublimates 2:15
Comets May Have Brought Water and Ingredients for Life to Earth 9:30

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PHOTOS/VIDEOS
Halley’s Comet, 1910 http://en.wikipedia.org/wiki/File:Halley%27s_Comet,_1910.JPG [credit: New York Times, Wikimedia Commons]
Bayeux Tapestry http://upload.wikimedia.org/wikipedia/commons/f/fa/Bayeux_Tapestry_32-33_comet_Halley_Harold.jpg [credit: Wikimedia Commons]
Comet McNaught [credit: Phil Plait]
Comet McNaught + tail http://en.wikipedia.org/wiki/C/2006_P1#/media/File:Cometmcnaughtchrisn1.jpg [credit: Chris North, Wikimedia Commons]
Comet surface http://rosetta.jpl.nasa.gov/sites/default/files/PIA18867-MAIN_Nov9-15765234852_c16c4097a5_o.jpg [credit: ESA/Rosetta/NAVCAM]
Fine structure in the comet’s jets http://blogs.esa.int/rosetta/2015/01/16/fine-structure-in-the-comets-jets/ [credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA]
Comet Halley http://apod.nasa.gov/apod/image/1001/halley_giotto_big.jpg [credit: Halley Multicolor Camera Team, Giotto Project, ESA]
Comet McNaught https://solarsystem.nasa.gov/multimedia/display.cfm?Category=Planets&IM_ID=10194 [credit: ESO]
Hubble’s Last Look at Comet ISON Before Perihelion http://en.wikipedia.org/wiki/File:Hubble%27s_Last_Look_at_Comet_ISON_Before_Perihelion.jpg
[credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)]
Hale-Bopp: The Great Comet of 1997 http://apod.nasa.gov/apod/ap131013.html [credit: Jerry Lodriguss, used with permission]
Sungrazer video http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=11307 [credit: NASA’s Goddard Space Flight Center]
“Large Web” graphic http://www.nasa.gov/sites/default/files/hs-2014-29-a-large_web.jpg [credit: JHUAPL/SwRI/Dan Durda]
Comet Daniel http://commons.wikimedia.org/wiki/File:Comet_Daniel_-_1907.jpg [credit: Max Wolf, Wikimedia Commons]
Vega 1 Low Res http://nssdc.gsfc.nasa.gov/planetary/image/veg2_tikf0002.gif [credit: Russian Academy of Sciences]
The Nucleus of Comet Halley http://sci.esa.int/giotto/51183-the-nucleus-of-comet-halley/ [credit: ESA/MPS]
Comet Hartley 2 http://en.wikipedia.org/wiki/103P/Hartley#/media/File:495296main_epoxi-1-full_full.jpg [credit: NASA/JPL-Caltech/UMD]
Comet 67P/Churyumov-Gerasimenko http://sci.esa.int/rosetta/54472-comet-67p-on-3-august-2014/ [credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA]
OSIRIS Catches Activity in the Act http://blogs.esa.int/rosetta/2015/04/20/osiris-catches-activity-in-the-act/ [credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA]
Active Pit http://www.esa.int/spaceinimages/Images/2015/01/Active_pit [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 http://en.wikipedia.org/wiki/Philae_(spacecraft)#/media/File:Rosetta%27s_Philae_touchdown.jpg [credit: DLR, CC-BY 3.0, Wikimedia Commons]
Colour Image of a Comet http://www.esa.int/spaceinimages/Images/2014/12/Colour_image_of_comet [credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA]
Comet Lovejoy http://en.wikipedia.org/wiki/C/2011_W3_(Lovejoy)#/media/File:Iss030e015472_Edit.jpg [credit: NASA/Dan Burbank]
NASA’s Stardust http://www.nasa.gov/images/content/361283main_sd_comet_2400x3000.jpg [credit: NASA/JPL]
Comet dust https://www.nasa.gov/images/content/141271main_jsc2006e01008_high.jpg [credit: NASA]
Comet Lovejoy http://www.eso.org/public/usa/images/dsc_5682-cc/ [credit: ESO/G. Brammer]

Comments

Saksham Kaushal says:

I am not able to understand COMETS..

Nabila Kaori says:

I'm thirteen and I barely understand the whole vodeo but is2g I WILL! goes to Google

ohsosmooth01 says:

I wonder if those "jets of gas streaming away…" are strong enough in themselves to alter the course of the comet?

ohsosmooth01 says:

I wonder if those "jets of gas streaming away…" are strong enough in themselves to alter the course of the comet?

Govinda Dasu says:

how do you tell a comet from an asteroid exactly?

Lily q says:

wait if coma means hair…. then why do we call a coma hair? ; oh ur father is in a coma

ur father is in a hair …?????????

abdolwahed says:

How did those amino acids that were found in the comet form?

Igor Stojanovic says:

I can not decide, Is this dude moron or arshole?
Ice???
What about deep impact?
You know… that cannon ball made of copper shoot at a comet? 🙂
What about all other complex molecule discovered
I have not heard so much selective B.S so tightly packed in 12 minutes for very long time.

Arianna Myrie says:

Woooo……we are all part alien….cool! Hmmmm, this poses the question, will other ones look like us, too?

usama rajput says:

suxh a informative lecture 🙂 thanks sir

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