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At his Psychology Today blog, Michael Chorost delves into a question about exoplanets that I've not really thought much about before — how easy they would be to leave.
Many of the potentially habitable exoplanets that we've found — the ones we call "Earth-like" — are actually a lot bigger than Earth. That fact has an effect — both on how actually habitable those planets would be for us humans and how easily any native civilizations that developed could slip the surly bonds of gravity and make it to outer space.
The good news, says Chorost is that the change in surface gravity wouldn't be as large as you might guess, even for planets much bigger than Earth. The bad news: Even a relatively small increase in surface gravity can mean a big increase in how fast a rocket would have to be going in order to leave the planet. It starts with one equation — SG=M/R^2.
Let’s try it with [exoplanet] HD 40307g, using data from the Habitable Exoplanet Catalog. Mass, 8.2 Earths. Radius, 2.4 times that of Earth. That gets you a surface gravity of 1.42 times Earth.
... it’s amazingly easy to imagine a super-Earth with a comfortable gravity. If a planet had eight Earth masses and 2.83 times the radius, its surface gravity would be exactly 1g. This is the “Fictional Planet” at the bottom of the table. Fictional Planet would be huge by Earth standards, with a circumference of 70,400 miles and an area eight times larger.
Does that mean we could land and take off with exactly the same technology we use here, assuming the atmosphere is similar? Actually, no. Another blogger, who who goes by the moniker SpaceColonizer, pointed out that Fictional Planet has a higher escape velocity than Earth. Put simply, escape velocity is how fast you have to go away from a planet to ensure that gravity can never bring you back. For Earth, escape velocity is about 25,000 miles per hour. Fictional Planet has an escape velocity 68% higher. That’s 42,000 miles per hour.
Thanks to Apollo 18, who also helped with the math for Chorost's post.
That's a picture of an Orthodox Christian priest, blessing the launch of a Soyuz spacecraft.
It seems like a weird and outdated pairing: Religion and space exploration. But they're actually a lot more intertwined than you might think, writes Rebecca Rosen at the Atlantic. A lot of astronauts are religious. A lot of astronauts that aren't really religious seem to have an urge to carry the cultural traditions of religion into space. And religion returns the favor. For instance, The Book of Common Prayer now includes an astronaut option in its prayer for travelers: "For those who travel on land, on water, or in the air [or through outer space], let us pray to the Lord."
I'm sorry. I'm an atheist and that just kind of gave me the shivvers. Basically, being out in space, so far from your fellow humans and in such an alien environment, makes for a really good example of the way religion (and ritual) can serve as a tie binding us to the rest of humanity. For some people, it's a connection to a bigger sense of history. And when they look the future (and/or the vast emptiness of space) full in the face, they need that connection to humanity. It doesn't work for everybody. But the relationship between religion and space travel is a good place to start when you want to have a conversation about the fact that there really don't have to be conflicts between religion and science. (Really, people. For serious.)
Here's the scene: It's Christmas Eve, 1968. The spaceship with three men on board had hurtled toward the moon for three days, and they have now finally entered the moon's orbit, a move requiring a maneuver so dicey that just a tiny mistake could have sent the men off into an unwieldy elliptical orbit or crashing to the moon's surface. But all went smoothly, and they are orbiting the moon. On their fourth pass (of 10), astronaut William Anders snaps the famous Earthrise shot that will appear in Life magazine. On their ninth orbit, they begin a broadcast down to Earth. Astronaut Frank Borman introduces the men of the mission, and, then, this:
"And the earth was without form, and void; and darkness was upon the face of the deep. And the spirit of God moved upon the face of the waters and God said, 'Let there be light," Borman read.
I can't remember who sent this story to me. If it's you, let me know, and I will credit you here!
A second launch attempt for the SpaceX Dragon spacecraft is scheduled for 3:44am EDT, Tuesday May 22. Weather is currently 80% go. Watch it live here. For background, watch Miles O'Brien's PBS NewsHour feature, and SpaceFlightNow's QA with SpaceX CEO Elon Musk. SpaceFlightNow will also have live coverage from Mission Control, with streaming video. (Image: SpaceFlightNow)
Participants in a rocket competition cheer after their rocket was successfully launched during the rocket festival known as "Bun Bangfai" in Yasothon, northeast of Bangkok, May 13, 2012. The festival marks the start of the rainy season when farmers are about to plant rice.
Chris sez, "My name is Chris Peterson. I run web communications for MIT Admissions and have been a loyal BB reader for years. For the last several years we have been sending our admitted students their acceptance letters in cardboard tubes. First because we sent a poster, but now it's its own thing. 2012 is the anniversary of an old MIT balloon hack, so we put a letter in all of the Early Action admit tubes telling them we wanted them to hack the tubes somehow, and set up http://hackthetubes.mitadmissions.org to collect responses. Lots of them are great, but this one, from Erin King (MIT '16) in Georgia, is the best."
Update: Erin sez, "I goofed on my Erin king 'MIT admit letter in space' submission. She is 17. I plain forgot what year it was - been too buried in applications!!"
It looks like Boeing will be the main competitor for Space X in the race to see what U.S. company will provide the commercial space flight services that NASA eventually plans to rely on.
Space X has its Dragon capsule, and Boeing is developing a new capsule system, called the CST-100. That capsule would ride into space under the power of an Atlas V rocket, an engineering descendant of the Atlas rockets that carried the first four American astronauts to space half a century ago.