Currently watching a webinar for eBooks for K12
Monthly Archives: January 2014
Apollo 1 anniversary
47 years ago today, Apollo 1 died, along with her crew: Gus Grissom, Ed White, and Roger Chaffee. It was to be the first launch of the Apollo Program, and the 3 crew members were doing a test on the pad. The mission was a low Earth orbital test, the first with the complex Apollo command module.
On January 27th, 1967, the crew were doing a “plugs out” test, where they tested that the command module would work without being connected to umbilicals and cables. The cabin interior was pressurized with a pure oxygen atmosphere, at a pressure slightly higher than outside air pressure. There was a voltage spike at 6:30 am, and shortly afterwards Chaffee exclaimed “Hey!”, and “I’ve got a fire in the cockpit!”. 17 seconds later, the transmission ceased as the command module ruptured.
There were multiple places where there could have been an ignition source, but later tests showed that the astronauts in nylon pressure suits, reclining on nylon flight seats and moving around normally could have generated enough electrical charge that touching the metal control panels would cause a spark.
The pressurized, pure oxygen atmosphere also contributed to the fire. Many materials become highly flammable in these circumstances. There were about 70 pounds of nonmetallic flammable material in the cockpit.
Further, the hatch was designed to not open if the cabin was at higher than atmospheric pressure. So the crew was unable to open the hatch without venting the extra pressure first, and the vent controls were near where the fire started.
While the mission never happened, and at the time the spacecraft was called AS-204, the designation was changed to Apollo 1: first manned Apollo Saturn flight – failed on ground test.
Say goodbye to the Peel Watershed of the Yukon
The new government of Canada’s Yukon territory is (most likely illegally) ignoring a 2011 agreement on how to treat the Peel Watershed. The watershed is 77,000 km2, of which some 67,000 are in the Yukon. The indigenous people have been fighting with the mining industry over land use. In 2011 the Peel Compromise set aside 80% as protected wilderness, with the other 20% open to mining.
The new government is very pro-mining, and feels that the agreement is null and void now that they have been elected. They are changing the 80% to 29%, with the other 71% open to mining.
This actually ties in with what I’ve been teaching my 6th graders. We just learned that the 3 main uses people have for land is agriculture, mining, and development. I’ll be bringing this up in class tomorrow.
Opportunity at 10 years (and still going)
The Mars rover Opportunity is starting its 10th year on Mars today. This is remarkable, because it’s mission was supposed to be 90 days long. That’s Mars days, or sols, which translates into 24 hours, 39 minutes, and 35 some seconds. Opportunity is still going. That’s 39.4704637 times longer than originally planned, and designed for; I wish my car was built this way.
Opportunity’s twin, Spirit, was also well over warranty when it became stuck in soft soil. At that point its mission changed from mobile laboratory to stationary observer. It sent its last transmission on 22 March 2010. We salute you Spirit.
These rovers (including Pathfinder/Sojourner and Curiosity) have made great scientific observations, including that Mars once had liquid water on the surface.
New supernova near Big Dipper
OK, not new. 12 million or so years ago. Anyway, up near the Big Dipper is M82, the Cigar Galaxy. After about 12,000,000 years the light of a Ia supernova has reached Earth. (that’s type 1-a) You’ll need a telescope of binoculars to see it. Here’s where it is in the night sky.As a type Ia supernova, it isn’t caused by a large star dying and collapsing. Instead, it is caused by a white dwarf accumulating enough mass to become unstable, or 2 white dwarfs colliding (rare). Because the accreting method leads to the mass of the white dwarf increasing until it reaches the Chandrasekhar mass (about 1.44 solar masses), where the temperature of the star reaches the temperature needed to fuse carbon. Once this happens, a lot of the star explodes, releasing about 1-2 × 1044 J of energy. This leads to a standard peak luminosity, which can be used to measure the distance to the supernova (they are standard candles).
The flu has struck!
Well, at least I think my son has the flu. He’s feeling miserable, and achy, and has a high fever, and would be horrified to know that I’m blogging about him. I’ve had the flu shot, but the rest of the family hasn’t. While it’s not my fault that my wife hasn’t had it, I have to take some responsibility for my son not getting it.
Anyway, you may want to take a look at google’s flu trends map, and check out the CDC’s flu information pages, including their map that shows that the flu is widespread.
Hope you’re healthy.
Interbreeding among different hominid groups
Just because there were different kinds of ancient humans doesn’t mean they were separate from each other. The Neanderthals (Homo neanderthalensis) coexisted with Homo sapiens for a long time. But there was interbreeding among the different species. A recent article in Nature talks about genetic analysis of different groups of proto-humans, showing that these groups interbred with each other. In fact, much of the diversity in our variations came about due to the interbreeding of H. sapiens to H. neanderthalensis and H. Denisovan. Depending on where you’re from, up to about 4% of your genome can come from one of these other species.
However, there is some controversy about these results. David Reich has better quality genome sequences that should be analyzed in light of this work.