The Oldest Star in the Universe

Hank tells the story of the mysterious star known as “Methuseleh,” and why scientists think that it is the oldest known star in the universe.

References
Watch Galaxies Collide: http://commons.wikimedia.org/w/index.php?title=File%3AAndromeda_and_Milky_Way_collision.ogg
Strange ‘Methuselah’ Star Looks Older Than the Universe: http://www.space.com/20112-oldest-known-star-universe.html
Hubble Finds Birth Certificate of Oldest Known Star: http://www.nasa.gov/mission_pages/hubble/science/hd140283.html

Is There Gravity in Space?

In a word, “yes” - space is packed with gravity. Hank explains how Isaac Newton described how gravity works, and why even though it seems that things are floating in space, they’re still effected by gravity.  Every object in the universe is constantly attracting every other object in the universe.

How Many Stars Are There?

How many stars are there in the universe? This question leads Hank to a couple other questions - How many stars can we see from Earth? How many stars are there in our galaxy? - but the answer to the original question proves elusive.

SciShow Great Minds: Henrietta Leavitt & the Human Computers

Henrietta Swan Leavitt was one of a number of volunteer women astronomers who were allowed to serve as “computers” at Harvard College Observatory, doing tedious work male scientists wouldn’t do, and ultimately making a discovery now known as Leavitt’s Law, which allows us to measure the distance to stars.

The Most Sophisticated Mirror in the Universe

Hank summarizes the five reasons why infrared telescopes were supposed to be impossible to build, and then describes how a team of scientists and engineers overcame those obstacles to build the James Webb Space Telescope.

Many thanks to Scott Willoughby and the entire team at Northrop Grumman for the tour.

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A note re: gold from Dr. Amber Straughn of NASA - “Gold is not the only “reddish” elemental metal (Copper is even more reddish) and other metal alloys are reddish or yellow (e.g., bronze, brass). The point is simply that gold is an excellent reflector of ALL the wavelengths of light that Webb is designed to see—from 0.6 microns out to 27 microns. Gold happens to look gold to us because it reflects blue light poorly, but this doesn’t matter because Webb doesn’t see light shorter than visible red. Silver is also an excellent reflector of IR, but it’s not as good as gold at ALL the wavelengths that Webb will observe.”

And re: the mirror - while the individual mirror segments have been completed, the full-size mirror has not yet been fully assembled and tested.  And though “polishing a 6.5m continuous mirror is incredibly difficult, it is not technically “impossible.”  In fact, a team at REOSC in France and at the mirror lab at U of AZ have been casting and polishing 8.4m optical primary mirrors for years now. But making the mirror in segments, in addition to making it deployable, makes polishing the mirror an easier-to manage process—basically polishing 18 small mirrors vs. one huge one, especially considering it is a mirror for an IR telescope operating at cryogenic temperature and enables easier transportation during the polishing and construction process (it’s really difficult, time-consuming and expensive to move a monolithic 8.4m primary—akin to moving the whole Webb observatory).”

Hank brings us news of the most sensitive digital camera in the universe, poised to help astronomers explain the mystery of why the universe is speeding up instead of slowing down as Einstein’s theory of General Relativity would predict.

expose-the-light:

Spectacular View of Two Seemingly Colliding Galaxies Captured By Hubble

Hubble has captured this beautiful new view of NGC 3314, two spiral galaxies located in the constellation Hydra, between 117 and 140 million light-years away from Earth. But they are not really colliding. If they were, they would look like this.

It’s an optical effect: NGC 3314A (on the foreground) and NGC 3314B (on the background) are just overlapping, separated “ten times the distance between our Milky Way and neighboring Andromeda galaxy.”

I just like to think they are in love and smooching. [NASA]

Hank briefs us on the upcoming planetary transit of Venus, which will be visible June 5th & 6th, 2012.

Beautiful video made from image sequences from NASA’s Cassini & Voyager missions.

Near-earth objects, primordial black holes, DNA discoveries, giant squid, radio telescopes & sending nuclear waste to the sun.