Aug 14 2010

Maybe we can go really fast after all?

Category: science,space — harmonicminer @ 8:10 am

Rethinking Einstein: The end of space-time Much more at the link.

IT WAS a speech that changed the way we think of space and time. The year was 1908, and the German mathematician Hermann Minkowski had been trying to make sense of Albert Einstein’s hot new idea – what we now know as special relativity – describing how things shrink as they move faster and time becomes distorted. “Henceforth space by itself and time by itself are doomed to fade into the mere shadows,” Minkowski proclaimed, “and only a union of the two will preserve an independent reality.”

And so space-time – the malleable fabric whose geometry can be changed by the gravity of stars, planets and matter – was born. It is a concept that has served us well, but if physicist Petr Horava is right, it may be no more than a mirage. Horava, who is at the University of California, Berkeley, wants to rip this fabric apart and set time and space free from one another in order to come up with a unified theory that reconciles the disparate worlds of quantum mechanics and gravity – one the most pressing challenges to modern physics.

Since Horava published his work in January 2009, it has received an astonishing amount of attention. Already, more than 250 papers have been written about it. Some researchers have started using it to explain away the twin cosmological mysteries of dark matter and dark energy. Others are finding that black holes might not behave as we thought. If Horava’s idea is right, it could forever change our conception of space and time and lead us to a “theory of everything”, applicable to all matter and the forces that act on it.

OK, I admit it. Whenever I run across one of these stories suggesting Einstein might be wrong about some aspect of relativity, I get excited, because if he was wrong about something, maybe he was also wrong about the speed of light being an absolute speed limit for everything except maybe “communication” between entangled particles and other exotica.

Because if we can’t ever go faster than the speed of light, it’s hard to see how interstellar travel ever becomes popular, and I like the idea of somebody someday zipping over to the next star system for lunch.

Of course, if interstellar travel really is impossible, we don’t have to sweat visits from unfriendly aliens who got mad at us when we didn’t write, and blew up the solar system, or just sterilized it.  On the other hand, if there AREN’T any aliens, or unfriendly ones anyway, it would be cool to terraform a few dozen other earthlike worlds (if there are any) and get a little lebensraum.  And it’s a cinch there aren’t any earthlike worlds (besides earth, of course) in our solar system.

So maybe I’m cheering the relativity revisionists, hoping one of them will find a loophole in the cosmic speed limit.

Who needed dark matter anyway?  And there is already enough dark energy in faculty meetings to keep the universe flying apart for the indeterminate future.

Jul 08 2010

Just in case they didn’t notice our candles, let’s turn on the searchlight? Or maybe not

Category: humor,illegal alien,Intelligent Design,science,space — harmonicminer @ 4:43 pm

A scientist who makes his living in SETI, searching for alien societies who might be communicating with us, says that It’s too late to worry that the aliens will find us

STEPHEN HAWKING is worried about aliens. The famous physicist recently suggested that we should be wary of contact with extraterrestrials, citing what happened to Native Americans when Europeans landed on their shores. Since any species that could visit us would be far beyond our own technological level, meeting them could be bad news.

Hawking was extrapolating the possible consequences of my day job: a small but durable exercise known as SETI, the Search for Extraterrestrial Intelligence.

Although we have yet to detect an alien ping, improvements in technology have encouraged us to think that, if transmitting extraterrestrials are out there, we might soon find them. That would be revolutionary. But some people, Hawking included, sense a catastrophe.

Consider what happens if we succeed. Should we respond? Any broadcast could blow Earth’s cover, inviting the possibility of attack by a society advanced enough to pick up our signals.

On the face of it, that sounds like a scenario straight out of cheap science fiction. But even if the odds of calamity are small, why gamble?

For three years, this issue has been exercising a group of SETI scientists in the International Academy of Astronautics. The crux of the dispute was an initiative by a few members to proscribe any broadcasts to aliens, whether or not we receive a signal first.

In truth, banning broadcasts would be impractical – and manifestly too late. We have been inadvertently betraying our presence for 60 years with our television, radio and radar transmissions. The earliest episodes of I Love Lucy have washed over 6000 or so star systems, and are reaching new audiences at the rate of one solar system a day. If there are sentient beings out there, the signals will reach them.

Detecting this leakage radiation won’t be that difficult. Its intensity decreases with the square of the distance, but even if the nearest aliens were 1000 light years away, they would still be able to detect it as long as their antenna technology was a century or two ahead of ours.

This makes it specious to suggest that we should ban deliberate messages on the grounds that they would be more powerful than our leaked signals. Only a society close to our level of development would be able to pick up an intentional broadcast while failing to notice TV and radar. And a society at our level is no threat.

The flip side is that for any alien society that could be dangerous, a deliberate message makes no difference. Such a society could use its own star as a gravitational lens, and even see the glow from our street lamps. Hawking’s warning is irrelevant.

Such considerations motivated the SETI group at the International Academy of Astronautics to reject a proscription of transmissions to the sky. It was the right decision. The extraterrestrials may be out there, and we might learn much by discovering them, but it is paranoia of a rare sort that would shutter the Earth out of fear that they might discover us.

Not everyone agrees.

Then there’s this, from a scientist who has written science fiction about nice aliens who “uplift” less than sentient species into full sophont status.  Maybe one of them would try to “uplift” humanity…

I’m not deeply worried that ET wants to come to Earth and eat us or something.  But if ET is out there, and can get here, and wants to get here, I really doubt that it would be out of a sense of altruism.  What if ET is at the same moral level as the Aztecs?  Maybe they believe in sacrificing low-level cultures (that would be us) to appease the Dark Energy God.

I mean, they could always just send a nice note, if all they want is to be pen pals.  And everyone knows it isn’t a good idea to meet in person with people you just met on Facebook….  let alone give them your home address.

Jun 29 2010

International Space Station Sex Ban

Category: science,space — amuzikman @ 8:55 am

From the London Telegraph:

Commanders do not allow sexual intercourse on the International Space Station. “We are a group of professionals,” said Alan Poindexter, a NASA commander, during a visit to Tokyo, when asked about the consequences if astronauts boldly went where no others have been. “We treat each other with respect and we have a great working relationship. Personal relationships are not … an issue,” said a serious-faced Mr. Poindexter. “We don’t have them and we won’t.”Mr. Poindexter and his six crew members, including the first Japanese mother in space Naoko Yamazaki, were in Tokyo to talk about their two-week resupply mission to the International Space Station. The April voyage broke new ground by putting four women in orbit for the first time, with three female crew joining one woman already on the station.Sexual intercourse in space may appear out of bounds, but astronauts have been known to succumb to earthly passions. In 2007 former NASA astronaut Lisa Marie Nowak allegedly wore adult diapers when driving hundreds of miles across the United States without bathroom breaks to confront a suspected rival in a romance with a fellow astronaut.

Given the sheer number and magnitude of problems facing us at home and abroad I can only say how relieved I am that this issue has been dealt with decisively.  I will now proceed to check it off my list of concerns.

May 06 2010

Time travel into the future?

Category: science,space,theology — harmonicminer @ 8:04 am

Time Travel Is Possible, Says Stephen Hawking

Famed astrophysicist Stephen Hawking believes humans are capable of time travel — and he’s not afraid to let everyone know.

Claiming he is not as concerned about being labelled crazy as he once was, Hawking has publicly aired his second startling theory in two weeks, after last week claiming it was “entirely reasonable” to assume aliens existed.

Preparing for the debut of his Discovery documentary, Stephen Hawking’s Universe, which screens next week, Hawking said he believed humans could travel millions of years into the future and repopulate their devastated planet.

Hawking said once spaceships were built that could fly faster than the speed of light, a day on board would be equivalent to a year on Earth. That’s because — according to Einstein — as objects accelerate through space, time slows down around them.

Which also means that Hawking’s theory only applies to moving forwards through time.

Moving backwards is impossible, Hawking says, because it “violates a fundamental rule that cause comes before effect.”

If moving backwards through time was possible, a person could shoot their former selves.

“I believe things cannot make themselves impossible,” Hawking said.

However, once spaceships approached the speed of light, their crew would start skipping through Earth years on a daily basis, giving the human race a chance to start again.

“It would take six years at full power just to reach these speeds,” Hawking said. “After the first two years, it would reach half light speed and be far outside the solar system. After another two years, it would be traveling at 90 per cent of the speed of light.”

“After another two years of full thrust, the ship would reach full speed, 98 per cent of the speed of light, and each day on the ship would be a year on Earth. At such speeds, a trip to the edge of the galaxy would take just 80 years for those on board.”

Manchester University professor Brian Cox told The Times that Hawking’s theory had already found some basis in experiments carried out by the Large Hadron Collider in Geneva.

“When we accelerate tiny particles to 99.99 per cent of the sped of light in the Large Hadron Collider at Cern in Geneva, the time they experience passes at one-seventhousandth of the rate it does for us,” Prof Cox said.

Hawking admits he is obsessed with time travel — he told the Daily Mail if he could go backwards he’d visit Marilyn Monroe in her prime or drop in on Galileo — but said as he got older, he cared less about what people thought of his theories.

“Time travel was once considered scientific heresy, and I used to avoid talking about it for fear of being labelled a crank,” he said in Stephen Hawking’s Universe.

“These days I’m not so cautious.”

We are all time travelers heading into the future, of course, just somewhat more slowly.

I’d love to know what kind of space-drive Hawking has in mind to achieve 98% of the speed of light.  Whatever it is, I doubt Al Gore will approve…  unless, of course, a galactic warming conference is being held in the Large Magellanic Cloud, in which case he’ll be sure to attend in his private light-speed yacht.

.

Apr 07 2010

Hanging on to the Shuttle?

Category: national security,Obama,Russia,science,shuttle,space — harmonicminer @ 8:03 am

Could moon rocket demise bring space shuttle reprieve?

The demise of NASA’s Constellation moon rockets is bringing faint hopes of a reprieve for the space shuttle.

NASA’s decades-old shuttle fleet has been headed for retirement since 2004, and only four more flights are scheduled. Now the White House’s plan to scrap the Constellation programme, a pair of rockets capable of taking astronauts back to the moon, has prompted renewed efforts to keep the shuttles running until new vehicles can replace them.

Two bills have been introduced in the US Congress to keep the shuttle flying while NASA works to develop replacements. The hope is that a modest extension, involving just a couple flights a year, could help retain jobs and maintain access to the International Space Station without relying on foreign launchers.

“If the space shuttle programme is terminated, Russia and China will be the only nations in the world with the capability to launch humans into space,” says Texas senator Kay Bailey Hutchison, who introduced the first of the two bills this month. “This is unacceptable.”

An extension to shuttle flights may struggle to win approval. Safety has been a concern, but a bigger hurdle may be money. The cost of a modest programme could exceed $2 billion per year, according to agency officials. “Where that money comes from is the big question,” shuttle programme manager John Shannon told reporters last week.

They seem to be able to find plenty of money in Washington for things that they think actually matter.  Does this matter?  Only if you think it’s fine for the USA to be dependent on Russia to get people into and out of orbit.

Obama obviously does.  Maybe he, too, has looked into Putin’s eyes and seen a man he can work with.

Or maybe Obama just doesn’t think it matters.

Mar 31 2010

Get ready to duck… but don’t bother to cover

Category: science,space — harmonicminer @ 8:43 am

Dark, dangerous asteroids found lurking near Earth

An infrared space telescope has spotted several very dark asteroids that have been lurking unseen near Earth’s orbit. Their obscurity and tilted orbits have kept them hidden from surveys designed to detect things that might hit our planet.

Called the Wide-Field Infrared Survey Explorer (WISE), the new NASA telescope launched on 14 December on a mission to map the entire sky at infrared wavelengths. It began its survey in mid-January.

In its first six weeks of observations, it has discovered 16 previously unknown asteroids with orbits close to Earth’s. Of these, 55 per cent reflect less than one-tenth of the sunlight that falls on them, which makes them difficult to spot with visible-light telescopes. One of these objects is as dark as fresh asphalt, reflecting less than 5 per cent of the light it receives.

Many of these dark asteroids have orbits that are steeply tilted relative to the plane in which all the planets and most asteroids orbit. This means telescopes surveying for asteroids may be missing many other objects with tilted orbits, because they spend most of their time looking in this plane.

Fortunately, the new objects are bright in infrared radiation, because they absorb a lot of sunlight and heat up. This makes them relatively easy for WISE to spot.

“It’s really good at finding the darkest asteroids and comets,” said mission team member Amy Mainzer of NASA’s Jet Propulsion Laboratory in Pasadena, California, at the Lunar and Planetary Science Conference in Houston, Texas, on Thursday.

WISE is expected to discover as many as 200 near-Earth objects, but astronomers estimate that the number of unknown objects with masses great enough to cause ground damage in an impact runs into the tens of thousands.

Richard Binzel of the Massachusetts Institute of Technology says the dark asteroids may be former comets that have long since had all the ice vaporised from their exteriors, leaving them with inactive surfaces that no longer shed dust to produce tails. He points out that many comets have very tilted orbits, and comets visited by spacecraft have been observed to have very dark surfaces.

I think I’ve met some people with tilted orbits lately.  Hey, ease up, it’s a joke.  But you can only seem to spot some of them with infra-red…

I’m glad there is Somebody watching over us.

Feb 23 2010

It is very sad

Category: energy,Obama,Russia,science,space,technology — harmonicminer @ 9:43 am

Charles Krauthammer – Closing the new frontier

“We have an agreement until 2012 that Russia will be responsible for this,” says Anatoly Perminov, head of the Russian space agency, about ferrying astronauts from other countries into low-Earth orbit. “But after that? Excuse me, but the prices should be absolutely different then!”

The Russians may be new at capitalism, but they know how it works. When you have a monopoly, you charge monopoly prices. Within months, Russia will have a monopoly on rides into space.

By the end of this year, there will be no shuttle, no U.S. manned space program, no way for us to get into space. We’re not talking about Mars or the moon here. We’re talking about low-Earth orbit, which the United States has dominated for nearly half a century and from which it is now retiring with nary a whimper.

Our absence from low-Earth orbit was meant to last a few years, the interval between the retirement of the fatally fragile space shuttle and its replacement with the Constellation program (Ares booster, Orion capsule, Altair lunar lander) to take astronauts more cheaply and safely back to space.

But the Obama 2011 budget kills Constellation. Instead, we shall have nothing. For the first time since John Glenn flew in 1962, the United States will have no access of its own for humans into space — and no prospect of getting there in the foreseeable future.

Of course, the administration presents the abdication as a great leap forward: Launching humans will be turned over to the private sector, while NASA’s efforts will be directed toward landing on Mars.

This is nonsense. It would be swell for private companies to take over launching astronauts. But they cannot do it. It’s too expensive. It’s too experimental. And the safety standards for getting people up and down reliably are just unreachably high.

Sure, decades from now there will be a robust private space-travel industry. But that is a long time. In the interim, space will be owned by Russia and then China. The president waxes seriously nationalist at the thought of China or India surpassing us in speculative “clean energy.” Yet he is quite prepared to gratuitously give up our spectacular lead in human space exploration.

As for Mars, more nonsense. Mars is just too far away. And how do you get there without the stepping stones of Ares and Orion? If we can’t afford an Ares rocket to get us into orbit and to the moon, how long will it take to develop a revolutionary new propulsion system that will take us not a quarter-million miles but 35 million miles?

To say nothing of the effects of long-term weightlessness, of long-term cosmic ray exposure, and of the intolerable risk to astronaut safety involved in any Mars trip — six months of contingencies vs. three days for a moon trip.

Of course, the whole Mars project as substitute for the moon is simply a ruse. It’s like the classic bait-and-switch for high-tech military spending: Kill the doable in the name of some distant sophisticated alternative, which either never gets developed or is simply killed later in the name of yet another, even more sophisticated alternative of the further future. A classic example is the B-1 bomber, which was canceled in the 1970s in favor of the over-the-horizon B-2 stealth bomber, which was then killed in the 1990s after a production run of only 21 (instead of 132) in the name of post-Cold War obsolescence.

Moreover, there is the question of seriousness. When John F. Kennedy pledged to go to the moon, he meant it. He had an intense personal commitment to the enterprise. He delivered speeches remembered to this day. He dedicated astronomical sums to make it happen.

At the peak of the Apollo program, NASA was consuming almost 4 percent of the federal budget, which in terms of the 2011 budget is about $150 billion. Today the manned space program will die for want of $3 billion a year — 1/300th of last year’s stimulus package with its endless make-work projects that will leave not a trace on the national consciousness.

As for President Obama’s commitment to beyond-lunar space: Has he given a single speech, devoted an iota of political capital to it?

Obama’s NASA budget perfectly captures the difference in spirit between Kennedy’s liberalism and Obama’s. Kennedy’s was an expansive, bold, outward-looking summons. Obama’s is a constricted, inward-looking call to retreat.

Fifty years ago, Kennedy opened the New Frontier. Obama has just shut it.

Dec 24 2009

Dodging the rocks

Category: science,space,theology — harmonicminer @ 9:26 am

The observation has been made recently that Life in the inner galaxy would be bombarded by comets

WE’RE lucky Earth resides in the Milky Way’s suburbs. Intense comet bombardment near the galaxy’s centre may make it tough for life to gain a foothold there.

Earth and the other planets of our solar system suffer occasional impacts when comets are disturbed from their orbits around the sun by the gravity of nearby stars and gas clouds.

The effect is stronger closer to the galaxy’s centre, where stars and gas clouds are more tightly packed. More than twice as many comets are shaken loose to potentially hit planets at half our distance to the centre, according to simulations by Marco Masi of the University of Padua, Italy, and his colleagues

People who study such things are telling us that the Earth is at the just-right distance from the galactic center, at the just-right distance from the Sun, with a just-right moon that creates tides, more critical for life than was once understood. The moon also helps keep the Earth at its just-right axial tilt so that we have seasons, which are sometimes annoying, but also critical for advanced life.

These facts are just the tip of the iceberg about the exceedingly rare “just-rightness” of our world for advanced life, and also the “just-rightness” of our world for intelligent life (that would be us) to be able to learn about the universe by observation.

Some people think this is a huge accident.

I don’t.

You can read more about this in these two books:

Rare Earth

The Priveleged Planet

Oct 20 2009

Earth and Jupiter in same photo

Category: science,space — harmonicminer @ 9:26 am

Stunning photo: Earth and Jupiter in the same shot

Sometimes the planets line up in such a way that you can see Earth and Jupiter in the same wide-angle shot. That is, if you were aboard the Mars Global Surveyor on May 22, 2003. When the Mars Orbiter Camera snapped this unique view, Earth was 86 million miles away, and Jupiter was 600 million miles away.

How on earth is it even possible to take such a shot? Continue reading to see a larger version of this magnificent photo, and then you can see a diagram of how the planets were lined up to enable such a thing.

Click the link above for a really stunning photo.

Jul 28 2009

Pluto making a comeback?

Category: science,space — harmonicminer @ 9:43 am

Is Pluto a planet after all?

Next week the IAU’s general assembly will convene for the first time since Pluto was axed from the list of planets. Surprisingly, IAU chief Karel van der Hucht does not expect anyone to challenge the ruling made in Prague, but Pluto fans can take heart: resistance remains strong.

If Pluto is reinstated, it will probably be thanks to discovery rather than debate. Mark Sykes of the Planetary Science Institute in Tucson, Arizona, believes that revelations within and beyond our solar system over the coming years will make the IAU’s controversial definition of a planet untenable (see diagram). “We are in the midst of a conceptual revolution,” he says. “We are shaking off the last vestiges of the mythological view of planets as special objects in the sky – and the idea that there has to be a small number of them because they’re special.”

And here I always thought Pluto was a dog.

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