In Space Without a Spacesuit? 90 Seconds in the Vacuum

10 seconds of consciousness, and 90 seconds for “minimal permanent injury”. Andrew Tarantola summarizes the actual science of What Really Happens When You Get Sucked Out of an Airlock.

Some degree of consciousness will probably be retained for 9 to 11 seconds (see chapter 2 under Hypoxia). In rapid sequence thereafter, paralysis will be followed by generalized convulsions and paralysis once again. During this time, water vapor will form rapidly in the soft tissues and somewhat less rapidly in the venous blood. This evolution of water vapor will cause marked swelling of the body to perhaps twice its normal volume unless it is restrained by a pressure suit.

— Parker and West (1973): Bioastronautics Data Book: Second Edition. NASA SP-3006.

The Dish

This is a question I occasionally get from students, so it’s good know where to find the studies, even though much of the evidence comes from accidents that happened to astronauts and cosmonauts.

Landing the Mars Rover: 7 Minutes of Terror

NASA gets dramatic. But the drama is oh so appropriate when you see what they have to do to land a rover on Mars. There are so many steps to the landing — heat shields, atmospheric friction, parachute, rockets — that it’ll be amazing if it works, and the video is a wonderful “strike the imagination” introduction to the physics of forces.

How to Watch a Meteor Shower

A meteor shoots past the Milky Way. Image by L.Brumm Photography and Design.

Space.com has an excellent guide about the best way to observe meteor showers; dress warm; after midnight; be patient). The Lyrid meteor shower is on this week.

To take good photos of a shower you’ll need to do long exposures or get lucky. Details on the photo above here.

Solar Flare

Just in time for our physics test — on electromagnetism — the Sun has had a Coronal Mass Ejection of charged particles that is heading toward the Earth.

[The Coronal Mass Ejection] is moving at almost 1,400 miles per second, and could reach Earth’s magnetosphere – the magnetic envelope that surrounds Earth — as early as tomorrow, Jan 24 at 9 AM ET (plus or minus 7 hours). This has the potential to provide good auroral displays, possibly at lower latitudes than normal.

— Fox, 2012: M8.7 Solar Flare and Earth Directed CME from NASA.

The Earth's magnetic field deflects charged particles around the planet, although some do get redirected down toward the poles, making the arouras. (Image from NASA's Spaceplace).

A Coronal Mass Ejection has about 100 billion tons of electrons, protons and other particles (NASA Cosmicopia, 2011), usually ionized, that would bombard the Earth and the atmosphere if we weren’t protected by the Earth’s magnetic field.

Most of the ions are deflected around the Earth but some get focused down toward the poles. At the poles, these ions hit nitrogen and oxygen molecules (that make up 98% of the atmosphere), exciting many of them. Excited atoms and molecules give off light. The light shows created are called the auroras.

Aroura australis, as seen from the International Space Station.

I like the second video they post because, at the end, there is a splatter of interference from all the charged particles affecting the detector.