BF2S Forums D&ST - Science

Spark wrote:

SenorToenails and topal63 are two of my most missed posters.

Jay wrote:

FEOS wrote:

Since when do toilets need power?

Converts waste into fuel.

The ABC conjecture, proposed independently by the mathematicians David Masser and Joseph Oesterle in 1985 but not proven by them, involves the concept of square-free numbers, or numbers that cannot be divided by the square of any number. (A square number is the product of some integer with itself). According to the mathematics writer Ivars Peterson in an article for the Mathematical Association of America, the square-free part of a number n, denoted by sqp(n), is the largest square-free number that can be obtained by multiplying the distinct prime factors of n. Prime numbers are numbers that can only be evenly divided by 1 and themselves, such as 5 and 17.

The ABC conjecture makes a statement about pairs of numbers that have no prime factors in common, Peterson explained. If A and B are two such numbers and C is their sum, the ABC conjecture holds that the square-free part of the product A x B x C, denoted by sqp(ABC), divided by C is always greater than 0. Meanwhile, sqp(ABC) raised to any power greater than 1 and divided by C is always greater than 1. [What Makes Pi So Special?]

This conjecture may seem esoteric, but for mathematicians, it's deep and ubiquitous. "The ABC conjecture is amazingly simple compared to the deep questions in number theory," Andrew Granville of the University of Georgia in Athens was quoted as saying in the MAA article. "This strange conjecture turns out to be equivalent to all the main problems. It's at the center of everything that's been going on."

The conjecture has also been described as a sort of grand unified theory of whole numbers, in that the proofs of many other important theorems follow immediately from it. For example, Fermat's famous Last Theorem (which states that a^n+b^n=c^n has no integer solutions if n>2) follows as a direct consequence of the ABC conjecture.

Spark wrote:

That's a hell of a photo.

White, who just shared his latest ideas at the 100 Year Starship 2012 Public Symposium, says that if you adjust the shape of the ring surrounding the object, from something that looks like a flat halo into something thicker and curvier, you could power Alcubierre’s warp drive with a mass roughly the size of NASA’s Voyager 1 probe.

In other words: reduction in energy requirements from a planet with a mass equivalent to over 300 Earths, down to an object that weighs just under 1,600 pounds.

What’s more, if you oscillate the space warp, White claims you could reduce the energy load even further.

“The findings I presented today change [Alcubierre's warp drive] from impractical to plausible and worth further investigation,” White told SPACE.com. “The additional energy reduction realized by oscillating the bubble intensity is an interesting conjecture that we will enjoy looking at in the lab.”

That’s right, an actual lab experiment, whereby White says he plans to simulate the tweaked Alcubierre drive in miniature, using lasers “to perturb space-time by one part in 10 million.”

And if it works? Don’t expect to go Alpha Centauri-hopping any time soon, but the idea well down the road, according to a presentation delivered by White on the subject last year, would involve a spacecraft leaving Earth, traveling a given distance using conventional propulsion, stopping (relative to the Earth), enabling its “warp field,” then traveling to a point near its interstellar destination, where it would then disable the field and continue on its way using conventional propulsion methods once more.

Star Trek meets Contact, in other words.

Instead of taking “decades or centuries,” White says this would allow us to visit a spot like Alpha Centauri — a little over four light years from us — in as little as “weeks or months."

F1 engines on their own are very loud but with the rocket also in full throat, the din produced in the shelter was predicted to exceed 180 decibels - many times the sound intensity of the Tornado fighters that used to occupy the building on the edge of the Newquay runway.