2017-04-26

[public] 569K views, 20.8K likes, 187 dislikes audio only

minutephysics

Support MinutePhysics on Patreon: http://www.patreon.com/minutephysics

Aatish Bhatia helped write this video! A big thanks for his help! Here's his blog: http://www.empiricalzeal.com

The universe is expanding – this we know from looking at red shifts of distant galaxies – but the acceleration of the universe's expansion is harder to measure. It requires measuring the change of recession velocity over time, and it's done by comparing Type Ia supernovas as standard candles at different distances, which is how we know the universe is accelerating!

Thanks to everyone who supports MinutePhysics on Patreon!

Link to Patreon supporters here: http://www.minutephysics.com/supporters.html

REFERENCES

Type Ia supernovae

http://hyperphysics.phy-astr.gsu.edu/hbase/Astro/snovcn.html

https://en.wikipedia.org/wiki/Type_Ia_supernova

Luminosity Distance

https://en.wikipedia.org/wiki/Luminosity_distance

Hubble diagram for type Ia supernovas (relatively close to earth): http://www.pnas.org/content/101/1/8/F3.expansion

http://www.astronomy.ohio-state.edu/~thompson/1101/lecture_fate_of_universe.html

Straightforward references:

Ryan Foley talking about WFIRST & Dark Energy

https://youtu.be/BhOAwXYKdmw?t=23m

Dark Energy FAQ:

http://www.preposterousuniverse.com/blog/2011/10/04/dark-energy-faq/

Why does dark energy make the universe accelerate?

http://www.preposterousuniverse.com/blog/2013/11/16/why-does-dark-energy-make-the-universe-accelerate/

David Spergel on dark matter & WFIRST

https://tvr2c.com/2016/06/01/53116-show-feat-professor-david-spergel-on-his-research-spanning-astrophysical-scales/

Slightly-technical references:

Permlutter article (old article but quite well explained & goes into future directions near the end)

http://supernova.lbl.gov/PDFs/PhysicsTodayArticle.pdf

Technical references:

Mukhanov’s Physical Cosmology

http://www.astro.caltech.edu/~george/ay21/readings/Mukhanov_PhysFoundCosm.pdf

Nobel Prize Summary

http://www.nobelprize.org/nobel_prizes/physics/laureates/2011/advanced-physicsprize2011.pdf

Cosmological redshift

https://en.wikipedia.org/wiki/Redshift#Expansion_of_space

MinutePhysics is on Google+ - http://bit.ly/qzEwc6

And facebook - http://facebook.com/minutephysics

And twitter - @minutephysics

Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!

Created by Henry Reich