Unbelievably Large Telescopes On the Moon? 292
Matt_dk writes "A team of internationally renowned astronomers and opticians may have found a way to make "unbelievably large" telescopes on the Moon.
'It's so simple,' says Ermanno F. Borra, physics professor at the Optics Laboratory of Laval University in Quebec, Canada. 'Isaac Newton knew that any liquid, if put into a shallow container and set spinning, naturally assumes a parabolic shape, the same shape needed by a telescope mirror to bring starlight to a focus. This could be the key to making a giant lunar observatory.'"
Re:Ob (Score:3, Informative)
New? (Score:4, Informative)
Hmmm...as the article notes, the idea of liquid mirror telescopes isn't new, so it seems a tad odd that this is being trumpeted as a breakthrough.
The ionic liquid coated with silver is cool, though.
Re:Wow (Score:5, Informative)
The difference is now they think they may have a liquid they can use - ionic liquids. On earth they use Mercury as the liquid but that is too heavy to lift to space and it will evaporate. Also the costs involved are now demonstrating it is viable for lunar use.
Re:Done on mythbusters-busted (Score:2, Informative)
Really? I wonder what they did wrong. Maybe they should have just bought plane tickets to Canada instead:
http://www.astro.ubc.ca/LMT/lzt/index.html
Re:Done on mythbusters-busted (Score:3, Informative)
it wasn't even part of a myth, it was part of a contest between two outside groups trying to start things on fire with mirrors. when they discovered that all teams were technically not fully within the rules they had to revise their mirrors, the one time tried to use plaster in a spinning platform to form parabola but it didn't come out with the correct shape so they had to abandon it. no myth was busted from this.
it was this episode [kwc.org]
Mythbusters wrong! Ohnoes!!one! (Score:3, Informative)
I know this isn't typical slashdottiness, but I actually read the article, and have some knowledge of telescopes in general. But since you won't believe me purely on my supposed knowledge, here's a quote from TFA:
And to add insult to injury (Uh Oh...): http://en.wikipedia.org/wiki/Large_Zenith_Telescope [wikipedia.org]
Yeah... They'll never work. Mythbusters said so.
Re:It WILL happen one day (Score:5, Informative)
The so-called "dark side of the moon" does not refer to the lack of sunlight or nighttime conditions. All parts of the moon go through the same kind of night/day cycle that the Earth does, only 29.53x slower.
The phrase refers to radio darkness. The moon spins at the same rate it orbits the Earth, so the same familiar craters are always facing us. Anyone standing amongst those craters is being bombarded by the radio noise chatter of the whole Earth population. Anyone standing on the opposite side of the moon can pick up none of that.
One potential problem with setting up bases on the dark side is how to communicate with them. To maintain the radio silence, you can't just stick a radio-based communication moon-satellite out there. It would be very expensive to maintain a cable or laser hookup for any significant distance along the moon surface. So you're left with small windows of time you can communicate, or you work on a focused laser-based comm link with a moon-satellite. That reminds me... what's the "geosynchronous" radius for moon-satellites?
Re:Done on mythbusters-busted (Score:3, Informative)
One hopes they have better things to do. Do you Slashdotters even read articles?
Some people who actually know what they are doing tried it and it [ok4me2.net] did work.
BTW the first working laboratory LMT was built in 1872.
Re:It WILL happen one day (Score:5, Informative)
Re:IANAPhysicist, but... (Score:5, Informative)
A lot.
The mass of the moon is ~7*10^22 kg (70 billion trillion kg). The mass of the Saturn V rocket is about 3 million kg. If we sent up a Saturn V rocket for every man, woman, and child on the planet, we wouldn't even be close to an appreciable fraction of a percent of the moon's mass. And even if we were, it is a stable system so there wouldn't be any significant effect.
Re:IANAPhysicist, but... (Score:5, Informative)
As I understand it, the moon's gravitational pull works against the earth's and the two are in a sort of balance that determines the distance of the moon's orbit, or something.
Yes, but the mass of the object is irrelevant. Very approximately, an orbit is where the outward force due to centrifugal force[*] is equal to the inward force due to gravity; both these terms scale linearly with mass, so if you increase the mass of one, the other increases proportionately and the balance remains.
(This is why the space shuttle and the space station can be in the same orbit a few metres apart, despite being different sizes.)
Also, in general the human race is nowhere near able to do any kind of cosmic engineering, deliberate or otherwise. Even if we bent all our resources to it, we wouldn't even be able to significantly resculpt the surface of our own planet, let alone another one.
[*] To pedants: yes, I know.
(BTW, the moon already is lopsided. The same tides that pull water around on Earth pulls the rock around on the moon. The near side of the moon is significantly larger than the far side. Interesting factoid: the moon is so irregular that setting up a stable orbit around it is really hard [nasa.gov].)
Re:IANAPhysicist, but... (Score:2, Informative)
Relax. The amount of mass is too small to make a real difference. The December 2004 earthquake that caused the Indonesian tsunami released more energy than we've ever produced/harnessed as a race, and consequently moved many orders of magnitude more mass than we will in the foreseeable future. Its effect on Earth's rotation was the barest fraction of a percent.
Re:Not Dark Side (Score:2, Informative)
I'd love to know the terminology used by other languages...
Don't make big plans, 'cause you're broke... (Score:5, Informative)
Don't make big plans, 'cause you're broke...
You can't have a trillion dollar bailout of the rich bankers, buy up every dishwasher's quarter-million dollar underwater mortgage, hold a permanent-endless war on the other side of the world, ... and have a giant telescope on the moon. It's not possible, it's science fiction.
All the space exploration projects being talked about and planned for the 2020's may actually happen...in the 2120's or 2220's. Not in ten years from now.
I know that you're all young and starry-eyed, but in the bankrupt USA, reality rules. And reality says that there isn't going to any giant new space program in the 2010's-2020's.
Don't just mod me to -1 for simply telling you the truth. And don't tell me how small the giant new space program is compared to other absurd federal government programs. Those programs are toast also.
My American friends...you are simply broke... you have dreams... but you have no money.
Re:Wow (Score:1, Informative)
It was suggested _many_ decades ago. Gallun in Astounding 1934.
http://www.technovelgy.com/ct/content.asp?Bnum=994
Re:Read TFA, sounds fundamentally flawed. (Score:3, Informative)
The solar wind. It "blows" which actually causes a static charge to build up twice a month as the Moon move into and out of the Earth's magnetosphere. This causes the dust to levitate because of electrostatic repulsion.