MASS

Episode 4 Heaven and Hell

The episode begins with the Tunguska Event in 1908 Russia. I'm always amazed that it took 20 years for Russia to explore the event. But when I see the extreme environment of a bug-infested swamp, I get a better comprehension for the difficulty.

He lists the size of incoming object as a football field (~100 meters). More recently I've heard the size estimate as 40 meters or 130 feet. I think additional research into the damage caused by air burst simulations has reduced the size required to cause the damage.

I'm amazed he listed the possibilities of it being an anti-matter object or an alien spaceship. In fairness, part of the episode was about not rejecting unlikely hypotheses just because they are weird. Hopefully, the recent Chelyabinsk event which occured uncannily close to Tunguska with a similar air burst will demonstate that a comet or stony asteroid can cause a lot of damage without leaving much debris or any crater.

Comets were always believed to be the harbingers of evil. Carl didn't call the sphere of comets around the Sun its current name of the Oort Cloud. I've read that the Oort Cloud might hold up to 2 trillion comets and begins about 2000 astronomical units (AU) from the Sun and ends just short of half way to the nearest star (~100,000 AU).  The AU is the distance from the Earth to the Sun or about 93 million miles. Alpha Centauri, the nearest star, is 4.3 light years away. There are 63, 115 AU in a light-year. Half the distance to Alpha Centauri is 135, 700 AU. For comparison, the Voyager 1 spacecraft that has been traveling since 1977 is only 126 AU away from the Sun about three times Pluto's  40 AU distance. Space is big!!

Venus is definitely a rough environment with a crushing atmosphere of 90 times that of Earth's and sulphuric acid clouds. The 900+ degree Farenheit temperature doesn't help the hostile environment either. Those conditions are definitely making Mars the exploration planet of choice. There hasn't been many recent launches to Venus. Europe's last launch was the Venus Express in 2005 and the US's last one was Magellan in 1989. Russia's last launches were in 1984 when a couple of Venus landers piggy-backed on Halley's comet missions.

He dwells a little about the relatively new science of Ecology and in the 10 year follow-up spends most of his time warning us that we must be should become better shepherds of the Earth's environment. Get more fuel-efficient cars, increase renewable energies and control our population explosion. 

Hope you enjoyed the episode. Let me know what you thought about it. 

Jim