Astronomy

The major Chile earthquake a few days ago appears to have shortened the length of Earth’s day by 1.26 microseconds (1.26 × 10^-6 or 0.00000126 seconds) and moved its axis by about 8 cm (3 in).

How could this happen?

Have you ever spun around in a chair and noticed that moving your arms in or out changed your speed? When you put your arms out you rotate slower and pulling them in makes you spin faster. It would seem that the earthquake caused a notable chunk of Earth’s mass to move closer to the center which caused the spinning Earth to speed up.

Source: Discoblog & CNN

So I’ve run into these videos before, but never realized they were part of a masterful series. The University of Nottingham has created 60+ ~5 minute videos each devoted to a symbol used in physics and astronomy.

http://www.sixtysymbols.com/

The Saturn and Jupiter videos were both great.

And a recent video all about Saturn’s most recently discovered (and very faint) ring. This is easily the best description I’ve heard of the ring and how it likely formed:
http://www.youtube.com/watch?v=_XgcPso9VHg

Check them out… they’re short, interesting, well made, and awesome.

Today’s Issac Newton’s birthday, the man who discovered the simple equations that predict the forces of gravity.

This simple equation is at the heart of Universe Sandbox. It’s what makes it all work.

And while his beautiful equation doesn’t work when you get really small or really big, it’s “adequate over an enormous range of masses of objects from about 10⁻²³ to 10³⁰ kg.” source

It’s amazing how something so simple can explain so much.

Happy Birthday Issac.

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For comparison: Earth’s mass about 6 × 10²⁴ and the Sun’s mass is about 2 ×10³⁰ .

More about Newton
http://en.wikipedia.org/wiki/Isaac_Newton

More about Gravity
http://en.wikipedia.org/wiki/Newton’s_law_of_universal_gravitation

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