Astronomy

More than 5 years ago on July 4, 2005, NASA crashed a 370 kg (815 lb) copper mass into the comet Tempel 1.

This impact kicked up more dust than expected and prevented the host spacecraft, Deep Impact, from getting a good photograph of the resulting crater.

Now more than 5 years later, another spacecraft, Stardust , has taken a photo of the impact site.
Before impact is on the left. After impact is on the right.

I have to say I’m disappointed by the result. The right photo appears blurry because it’s taken from much further away than the composite on the left and the crater isn’t very obvious even with the yellow arrows pointing it out.

What is amazing is that humans impacted a comet, then flew by it again with another spacecraft years later to take a follow up photo. Even thought the image isn’t as visually impressive as what one might expect from a collision, there’s lots for scientists to learn from it and what happens when you slam something into a comet at 10 km/s (about 1/3 the speed the Earth travels around the Sun).

You can learn more about the impact from Bad Astronomy’s analysis of this event and their follow up post.

In Universe Sandbox you can slam moons into the Earth, Earths into Jupiters, or Jupiters into Sun to your hearts content.

Launch Earth at Jupiter

1. Download & Install Universe Sandbox (it’s free and includes a 60 minute trial of all the premium features, including the add and launch tools)
   You may want to run through the short tutorial to get a feel for how to navigate in the simulator.
2. Open the Jupiter & Moons simulation.
3. Select the Add Tool (the Saturn icon with the +) and then select the Earth icon.
4. Select the Launch tool (looks like a crosshair) and click on Jupiter to launch Earth at it.
5. Keep clicking to launch more than one.

The Kepler space telescope, designed to find planets around other stars, has found an amazing little solar system. Affectionately named Kepler-11, this solar system has 6 planets (all larger than the Earth), with 5 of those planets in a super close orbit to their Sun like star.

Open the Kepler-11 simulation on your computer

1. Download & Install Universe Sandbox (it’s free and includes a 60 minute trial of all the premium features)
   You may want to run through the short tutorial to get a feel for how to navigate in the simulator.
2. Download the Kepler-11 Solar System simulation.
3. Open the simulation by either dragging the downloaded file into the Universe Sandbox window or by double clicking on it.

Check out the Bad Astronomer’s article for more on how humanity made this discovery.

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Here’s a view of the complete Kepler-11 system. Note the size of the Sun is to scale with the entire simulation (it hasn’t been scaled up). The orbit of our Mercury (the closest planet to our sun), would be just slightly inside the orbit of g. In Universe Sandbox you can turn on the Solar System grid to clearly see this comparison.

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Universe Sandbox’s Chart mode, by distance, view of the system. The colors and textures are mostly guesses, but astronomers are quite certain of the sizes. I’ve included our Earth for comparison. The white mass on the left is the Kepler-11 sun.

More Information

• Wikipedia article about Kepler-11
• Exoplanet database info on Kepler-11

NASA’s Solar Dynamics Observatory, a brand new spacecraft launched in February, has began sending back the most amazing and highest quality images of the sun ever taken by humanity.

More amazing images and video
http://science.nasa.gov/science-news/science-at-nasa/2010/21apr_firstlight/

Official site of the spacecraft
http://sdo.gsfc.nasa.gov/

Wikipedia Article
http://en.wikipedia.org/wiki/Solar_Dynamics_Observatory

Space is constantly raining down about 100 tons of interplanetary material each day. Usually it’s just dust, but sometimes it’s in larger chunks that crashed into the State of Wisconsin (United States) last night (on April 14, 2010).

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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