Thursday, February 23, 2017 8:26 AM
The discovery of seven earth-sized planets orbiting a dwarf star, Trappist-1, makes me wonder how big the ‘goldilocks’-zone is, when talking of a star that isn’t much bigger than Jupiter—and if the orbits of all seven planets could all fit in that little slice of space. Being the same size as Earth means the gravity would be the same—but without placement in the ‘goldilocks’-zone, a planet will be too cold or too hot to live on.
I’m so used to thinking in terms of science fiction that it’s hard for me to get excited about seven planets orbiting a dwarf star forty light-years from Earth. But even from a non-fiction point of view—forty light-years is a ‘fer piece’.
Do the math: one light-year equals 5.8 trillion miles (that’s 10 to the twelfth, for those of you playing at home). Here—we’ll do it the kids’ way: 5,800,000,000,000 miles. That is a very long walk. If we traveled at 1,000 mph, it would take about 6,600 years to travel one light-year. If we traveled at 10,000 mph, it would still take over 660 years to travel one light-year. Thus, in practical terms, a light-year is a distance that a person has never traveled—and has no way of traveling, at present, within a single lifetime. The new solar system that was just found—that’s forty-of-those-things distance from us—that’s just a ridiculous distance away.
Light-years, the unit of distance, was created by and for astronomers—it allows astronomers to discuss the relative distances of stars—but don’t let that fool you into thinking of light-years in terms of human travel—it’s not a human scale of distance.
Plus, if you want to fly through space at 10,000 mph for 660 years, you’re going to need a very big gas tank. Carl Sagan told us that we could avoid this problem by using a Bussard ramjet, a spaceship that collects hydrogen atoms as it moves forward—and uses fusion to propel itself. The Bussard ramjet would use the near-vacuum of space as its fuel—imagine!
But that still leaves you with the need for food, water, and breathable air for however many people for however many years—and even with great recycling tech, that’s a lot of supplies to push through space. And again—forty light-years—if we could travel one light-year, we’d still need to do it forty times to reach that dwarf star with its seven planets.
Also, once you arrive at the dwarf star, you are completely cut-off from Earth—and Earth from you. Forty light-years means that even a radio message would take forty years to go in one direction—which means, if you got on the phone, said ‘hi’, and waited for the other end to say ‘hi’ back—that’s eighty years.
If we ever send people out there, we won’t be ‘colonizing’, we’ll just be sending little samples of humanity out into the cosmos. Maybe their great-grandchildren will communicate with Earth, but never in a “Hi, How are ya” kind of way. Assuming they survived, they would become a totally separate civilization from our own.
And this is the sad truth—space exploration will not ‘save’ the Earth. Sending people to space, even into our local solar system, will help protect the human race from extinction—but it won’t do anything for the people that remain on Earth. And living in space will never be as safe and easy as living here, on the cradle of life.
There is enough raw material in the asteroid belts and the Oort cloud for us to build several ‘earths’—but we will never be able to move significant numbers of people up from Earth ‘s gravity well without a space elevator—and we still don’t have the technology to build one of those.
In summary, space exploration is not easy or simple. It will take more determination than the human race has shown itself capable of, to date, to get there in any meaningful way. People often theorize that an alien invasion would help to unify the human race—and, in the same vein, the destruction of our biosphere would help to motivate people into space. But why do we need a global disaster to get our asses in gear? Can’t we just be grown-ups? Let’s reach for the stars.