One minute video explanation of "dark energy"

A one minute video explaining the concept behind the Nobel-winning physics discovery that the universe is rushing away from us at an accelerating pace? Take it away Sean Carroll.

Sean is a CalTech theoretical physicist. He appeared at the 2010 IdeaFestival, and recorded this video on the arrow of time that you may enjoy.


Wikipedia: dark energy

Lee Billings - "Planets Pour Out of the Sky"

“Two possibilities exist: either we are alone in the Universe or we are not. Both are equally terrifying.” Arthur C. Clarke

Lee Billings is the author of Five Billion Years of Solitude and is speaking today at the IdeaFestival. He starts at the VERY beginning.

It's been 13.8 billion years. "Let me congratulate you on the improbable achievement of being here.... Most of the universe is empty space."

Spreading his arms wide, he suggests that if all of time were contained within his reach, human existence could be scraped away with a nail file. Moreover, cosmically speaking, we are perhaps nearer the end of complex life on earth than its beginning. And if we want to have a future after the next 500 million years, when planetary life will become untenable because of the changes in our sun, we might want to think of alternatives. We're capable, he says, of "choosing our own cosmic fate."

In the meantime, the search for life elsewhere "can give valuable context to life right here on this small cosmic speck of dust." Turning to the subject of his talk today, he points out that science and technological progress tell us that planetary formation is common.

In fact, planets are now "pouring out of the sky." He believes that 10,000 confirmed finds will soon be in the exoplanet catalog, which only came into existence in the past 20 or so years. Plotting those finds on a graph overhead, he points to "walls of worlds" discovered in just the past three or four years thanks to the space telescope Kepler. Interestingly, he says, Kepler has told us that OUR planetary system is atypical. 

Billings walks the audience through two basic exoplanet detection techniques, the transiting and radial velocity methods. "Wobbles give you size. Transiting gives you mass." Kepler uses the transiting method.

The data so far, he is quick to add, doesn't support some of the wilder claims for habitable Earths that have reached the popular press. We're just in the formative stages of a new science. He explains that as late as the 1950's, many informed scientists believed that Venus might be a terrific place to live. It's emblematic, he says, of where exoplanetology is today.

Since direct observation of worlds tens of thousands of light years away is problematic because the competing light from the host star overwhelms the reflected light from nearby planets, we know what we know about the suitability of worlds for life based, in part, on how light interacts with chemicals as it passes through a planet's atmosphere on its way to our telescopes. Those signatures can be teased out in spectrographic prints to tell us what what molecules are present above the host body.

Thanks to that technique and the evidence offered by robotic explorers, we now know that Venus' crushing atmosphere is suffering from a runaway greenhouse effect. It would be a terrible place to live.

In the next few years, the enormous James Webb telescope will be able to peer at nearby stars to look for water vapor. And we could fund additional searches, but the trade-offs in a time of budget cuts are hard. One proposed exoplanetary telescope, for example, was killed in favor of funding two more Space Shuttle missions.

Meanwhile, "the planets are piling up." Asked during Q&A about what it would mean to find microbial life in our own planetary neighborhood, Billings believes it would be "disconcerting." If primitive life thives nearby, it means that, like planatary formation, it too is a common phenomenon.

And since we haven't heard from intelligent life elsewhere, is there a "filter" along this developmental path that prevents intelligent civilizations from flourishing?

The question lingers.


Thank You!

Thank you for making IdeaFestival 2011 so wonderful! We couldn't do it without you, our fans and sponsors, who for four days make the IdeaFestival the most creative and inspiring place to be in the world.


Image: Geoff Oliver Bugbee

Will Shortz on the"Grab-bag Brain" - IdeaFestival Conversation

New York Times crossword editor, puzzle master for npr's Weekend Edition Sunday and enigmatologist, Will Shortz, on the "grab bag brain". Filmed in Louisville, Kentucky at the ideafestival, September, 2008.
From: IFTV
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Claudia Hammond - Time Warped, Our Minds Play Tricks on Us

As often happens at the IdeaFestival, we begin asking more questions than we can answer. Such is the case at this afternoon’s Time Warped session with Claudia Hammond.

BBC reporter and psychologist, Hammond has been mulling over the question of time-perception for quite a while (in real time). 

She opens today’s talk by describing what happened to Alan Johnston, a BBC journalist who was kidnapped and held hostage in Gaza for four months.

“When the gun was put to his head,” Hammond says, “time slowed down.”

Johnston had no watch or clock. He could not see the sun rise or fall. He began to contemplate the psychology of time.

We often hear how a moment can feel like an eternity. But this is not just a cliche— it’s real.

And even less extreme cases, Hammond reminds us, illustrate the point. A 30-minute lunch break with a friend will often feel rushed; if you’re spending that time waiting in line, it’s a different story.

Hammond is interested in the psychology of time. How does time FEEL? Our minds, she says, are vulnerable; time can play tricks on us.

Psychologists have shown ways that we can be manipulated.

In 2003, psychologists gave 50 people name tags and asked them to chat with others in the group. Afterwards, the subjects were asked to form pairs with the people they were getting along with. Then, the experimenter took half of the group aside, each person individually, and told them (falsely) that no one had selected them as a partner. The experimenters told the other half (falsely) that everyone had selected them as partner. Then, each person proceeded to work on a task individually.

The rejected group, perhaps not surprisingly, felt time pass more slowly. 

So emotional state has an effect on time-perception. Happy people perceive time moving faster. Depressed people feel time passing more slowly.

“We actively construct in our mind how much time is passing,” Hammond says. 

Emotions play into time-perception in another way; the experiences we find meaningful (as well as new experiences) resonate more deeply; we will feel time moving more slowly through those moments.

Are you paying attention?


Hope Reese @hope_reese

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