Space Fan News #50: How Much Dark Energy Is There Really?; NASA Will Launch NuSTAR

http://gplus.to/TonyDarnell
http://facebook.com/SpaceFan


Full 3D Picture of the universe:
http://www.sdss3.org/press/20120111.sloanguide.php
http://newscenter.lbl.gov/news-releases/2012/01/11/what%E2%80%99s-in-the-univ...
http://darkmatter.ps.uci.edu/lrg-sdss/

NuSTAR
http://www.nasa.gov/mission_pages/nustar/main/index.html
http://www.nustar.caltech.edu/about-nustar

Category:

Science & Technology

Tags:

• dark energy
• SDSS
• galaxies
• astronomy
• cosmology
• NASA
• Space
• NuSTAR
• CMB

[NICOLECALDERERO61]

i love watching Tony Darnell's videos about updates on astronomy, physics and downtown...

[cipher2]

I heard there was no sound in space, if so then how can we study sound waves? Clarification on this much appreciated, please respond.

[n2motocross]

If they ever have an opening on the T.V. series 'Big Bang Theory'.,,,He will be a shoe-in.

Great video by the way.

[saultube44]

Thx for the video, is the short & comprehensive version of the latest astronomical discoveries. Thumbs up.

[pseudorandomly]

@somthinjustaintright

In air at Earth-atmosphere pressure, you can produce a "sound" wave by simply waving your hand back and forth. The frequency is too low for your ear to perceive, but it is nonetheless very low-frequency "sound". The principle works in extremely low-density gas, too, just as in your example -- you just need a much bigger paddle than your hand to get a pressure wave started.

[somthinjustaintright]

@pseudorandomly Right, but how can sound waves travel through a "cloud" of, e.g. the Helium, through which our solar system is passing. There is less than one atom per cubic meter. I might have the numbers a bit skewed but I think the idea  works. Thanks

[pseudorandomly]

@somthinjustaintright

In the broadest definition, "sound" is just a pressure wave in matter. Pressure waves in air are what your ear perceives as speech, music, and other noise. Pressure waves in the Earth are what shakes the ground in earthquakes. Pressure waves in the ultrathin gas of interstellar space can trigger star formation. Pressure waves in the early Universe caused the slight temperature variations of the cosmic microwave background. All "sound" in the largest sense.

[pseudorandomly]

@bicnarok

These are difficult measurements, and, as all experiments, subject to certain levels of experimental error. Also, different methodologies are used, which may lead to somewhat different results. Dark matter is clumpy, so observations that measure dark matter and then calculate averages will not surprisingly lead to numbers that are a bit different than, say, calculating values from the slight anisotropy in the cosmic microwave background. By no means are these "guesses".

[cipher2]

@Mallaclllypse Thank you for taking the time to explain. I understand now, wheeeeeew!!!!

[Mallaclllypse]

@cipher2 @somthinjustaintright if you look at the map at 3:18 (CMB) it shows the distribution of matter in the universe when it was only about 380´000 years old. At this point the universe had no stars or galaxies, but instead was a hot, dense cloud of plasma that was dense enough to allow shockwaves to travel through it. Just like sound does here on earth or in the oceans.So they are not measuring sound travelling to us, but the effect of the shockwaves interacting with the plasma.

[rev0lut10nz]

Thanks for the great vid.

[1maN008]

565 likes and 0 dislikes... This shows how amazing your video is!