THE SOUTHWORTH PLANETARIUM
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70 Falmouth Street Portland, Maine 04103
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Founded January 1970
"Binge watchers"
THE DAILY ASTRONOMER
Thursday, April 21, 2016
Impossible Warps and Other Wrinkles
Pandora's Jar is something of a cornucopia. The faster one attempts to deplete it, the faster it fills back up. One can well understand this self-replenishing behavior by realizing that every answer generates other questions. Like the furious Hercules who frantically severed Hydra's heads only to discover that they had proliferated beyond all control, we have endeavored to empty Pandora and it remains stuffed with parchments. And, honestly, this is utterly fantastic! We intend to write these articles until time, itself, crashes to a shattering halt, so the more material we have, the better.
Today's papers bring us to the realm of the distant and impossible.
"As a Star Trek fan, I wonder....is warp speed actually impossible?"
-M. Spock, Portland (Yes, that's not my real name)
Well, Mr Spock, as far as we know, warp speed is impossible for any massive object. We should explain for the benefit of those who've never watched "Star Trek" that warp speed is light speed. And, Warp 2 is twice light speed; Warp 3 is three times light speed and so forth. Albert Einstein's Theory of Special Relativity (1905) tells us that light speed is the maximum attainable velocity. Here, we're referring to light speed in a vacuum, which equals 299 792 458 m / s. Also, the faster a vessel moves, the greater its mass becomes.
You see, motion induces three effects onto any object: time dilation, mass increase, and length contraction. The faster the motion, the greater these effects become. Moreover, when moving at light speed, time stops, mass becomes infinite and the object contracts down to a singularity. (A mathematical point of no dimension.)
These effects preclude any vessel from approaching light speed, let alone attaining or exceeding light speed.
Warp speed is a handy device for science fiction authors, but physically, the notion of Warp speed is more problematic. According to the Theory of Special Relativity, light speed is the maximum attainable velocity. No material object, including the U.S.S. Enterprise should be able to even approach light speed, let alone attain or exceed it.
Of course, physics is a tricky business. Some hitherto unkmown property of space-time might permit spacecraft to overcome this barrier and traverse outer space at hyperluminal velocities. Such speeds would be necessary for an interstellar journey because even the closest stars are a few light years away from us. Perhaps black holes could be utilized for this purpose. Or. more precisely, the Einstein-Rosen Bridge (Wormhole) beyond black holes could serve as a conduit to distant points in space. Unfortunately, any astromaut approaching a stellar mass black hole would be torn asunder by the black hole's tidal forces before he was able to come within 100 miles of the black hole, itself.
So, the answer is that warp speed seems impossible...but wait a couple centuries to see what future physicists discover.
And, an earlier DA this week about outrunning the lunar terminator prompted this question:
"But, with the reduced gravity on the moon, and the increased bulk of the necessary space suit, would more of us be able to outrun the terminator?"
-P.B. Earth
That raises an interesting point. First, we know that the difference between walking and running is that one must lift both feet off the ground in order to run. (Broncos' offensive coordinator take note.) Also, when running on Earth, the planet's gravity draws one back to the surface rather rapidly, so a runner is constantly making strides and propelling herself forward. The moon's gravity is 1/6th as powerful as Earth's, so every time a runner pushes her feet on the surface, she rises higher and takes longer to return to the ground. Even if the astronaut wears hundreds of pounds of equipment, she'll still likely weigh less than a hundred pounds on the moon. (For instance, the Apollo Astronauts and their suits weighed about 480 pounds on Earth, but only about 80 pounds on the moon.)
Buzz Aldrin looks on as Neil Armstrong -visible in Neil's Visor- moves on the moon's surface. The moon's gravity isn't as strong as Earths, so moving would be easier. However, a fast run on the moon wouldn't be easy as every stride takes much longer to complete in such a low gravity environment. (Image: NASA)
This reduced weight would help an Earthling move more quickly on the moon. After all, if you walk a lot, your muscles are conditioned for your Earth weight. If, suddenly, you weigh far less than you did, your muscles can move you more efficiently. However, one would find running on the moon to be problematic because one doesn't just immediately fall back to the surface. Instead, one rises and then descends slowly. A rapid sprint wouldn't be easy on the moon. A runner would instead move in wide leaps and bounds. If, perhaps, one could push oneself with sufficient force, one could perhaps keep ahead of the terminator, at least for awhile. Nevertheless, it would be easier far away from the equator.
"When will Halley's Comet return? Has it even turned around yet?"
-Paula S, Cape Elizabeth
Halley's Comet last passed through the inner solar system in 1985-6. Its orbital period is approximatey 76 years, so it is due to return in 2061-62. (It is scheduled to reach perihelion, the closest point to the Sun, on July 28, 2061). As cometary orbits are elongated and comets are small, perturbations induced by other solar system objects can effect these periods, rendering them slightly uncertain. Halley is approaching the most distant point in its orbit (called "aphelion"), which is about 3.2 billion miles from the Sun. It should reach aphelion around 2024. It will then slowly trudge back toward the inner solar system for its 2061 solar fly by.