Artist’s impression of the the planet orbiting the star Alpha Centauri B. CREDIT: ESO/L. Calçada/N. Risinger

Despite the hundreds of extrasolar planets found so far, the discovery of a planet orbiting the nearest star to our Sun has extraordinary consequences for astronomers and the public alike.

The Sun’s nearest neighbor is a multiple star system that lies merely 4.3 light years away – a galactic stone’s throw.

Alpha Centauri is only clearly visible from southern skies as a brilliant white star (it is actually two stars that are too close together to be seen separately by the naked eye). The faint third member of the system, a red dwarf star Proxima Centauri, yields no evidence for planets and is so far from the binary pair as to be inconsequential.

The European Southern Observatory reported the planet discovery on October 17. An instrument called the High Accuracy Radial velocity Planet Searcher, or HARPS, precisely measured small wobbles in the slightly smaller companion star, Alpha Centauri B. This yielded telltale evidence for the presence of an Earth-sized world whirling around the star, completing an orbit every 3.2 days.

The bad news is that the planet is too close to the star to support life as we know it. The surface roasts at over 2,000 degrees Fahrenheit – hot enough for hellish oceans of molten magma.

Alpha Centauri A & B are separated by as much as two billion miles. According to models, they are each capable of forming terrestrial planets despite the perturbing influence of a binary companion. In fact, a companion star can be a gravitationally stabilizing influence, like massive Jupiter is in our solar system.

On the heels of this discovery, the Alpha Centauri system is ripe for far-future exploration. That’s because NASA’s planet-hunting Kepler observatory is showing us that entire planetary systems are common. Kepler has identified several thousand other exoplanets, though most remain to be confirmed by follow-up observations.

What’s more, Kepler is finding that rocky Earth-sized planets are increasingly common. (Kepler is monitoring over 150,000 stars in the constellation Cygnus for telltale planet transits, and Alpha Centauri is not in its field of view). Therefore, it’s probably only a matter of time before other observations turn up additional planets at Alpha Centauri.

It’s also possible that one or more planets could be in the stars’ habitable zones, where temperature are mild enough for stable oceans to exist. The discovery of such a world would eventually be followed by a large enough optical-infrared space observatory that could spectroscopically sample the planet’s atmosphere. Attempts would also be made with NASA’s upcoming 6.5 meter mirror James Webb Space Telescope.

If spectroscopic observations made perhaps with an 8- to 16-meter mirror space telescope confirmed that a planet’s atmosphere has biotracers – such as oxygen, ozone, nitrous oxide, methane, and chlorine – there would be motivation to build a dedicated interferometric array of optical space telescopes. Observations could reveal the waxing and waning of continents and oceans as the planet rotates, and the changing tapestry of weather patterns. SETI observations would monitor the planet for evidence of alien telecommunications.

Today’s fastest space probes would take 40,000 years to get to Alpha Centauri. But by the next century, there could be attempts to send a small probe to the system at extraordinarily faster speeds. Such a mission would have a cruise phase of only 40 years if the technology were to develop for extraordinarily powerful propulsion systems that could accelerate a probe for 10 percent the speed of light. That no small task, but it doesn’t require some imaginary warp drive, simply Newtonian physics. The builders of the spacecraft could live long enough to see data returned from Alpha Centauri.

An ambitious mission would enter orbit around any potentially habitable planet. Robotic landers would be dispatched to observe life up-close and personal. We could behold the effects of Darwinian evolution on an extraterrestrial Serengeti of unimaginably exotic creatures.  By the time we are ready for such a mission we will have matured the required artificial intelligence and nanomachine technology. The autonomous probe would direct its own exploration mission.

Because Alpha Centauri A and B are Sun-like in terms of age and temperature, there has been plenty of time for life to develop on any planets we might find in the habitable zones around either star.

The view from a terrestrial planet in an approximately Earth-sized orbit around Alpha Centauri would certainly be exotic to our experience.  At one point during the planet’s year, the two stars would be in conjunction – in other words, side-by-side in the sky. The closer star would have a glowing disk like the Sun; the other would be more star-like and far more brilliant than Venus.

A planet would be influenced by the radiation from both stars. Every 70 years Alpha Centauri A & B come closest to each other. Warming on an Earth-like world would be brief but intense, raising planet-wide temperature by a few degrees.

Given the awesome power of biological evolution, life would evolve to cope with living with a second star. Life on such a planet might develop two circadian rhythms corresponding to both the length of day on the planet, and orbital period of the binary stars.  There may be planet-wide migrations in anticipation of the approaching “super-summer.” And, there would be a variety of other novel coping mechanisms.

If there were intelligent life present out there, Alpha Centauri astronomers would routinely turn their attention on a bright first-magnitude star in the W-shaped constellation Cassiopeia. It would be our Sun. And the astronomers might muse on what life would be like around a single yellow dwarf star.

Hubble’s eXtreme Deep Field

On September 25, 2012, Hubble released another “deepest image ever taken of the universe,” this one called the Hubble eXtreme Deep Field. This image shows more galaxies, fainter galaxies, and farther galaxies than any other image before it. Within the new deep field image are a handful of galaxies located about 13 billion light-years away. And, since the light from those galaxies has taken 13 billion years to cross the intervening space, we see these galaxies as they were less than a billion years after the beginning of the universe.

We can look out in space, and thus back in time, to see galaxies and the formation of galaxies just after the Big Bang. How’s that for a deep thought? Consider it as you watch this video showing the tiny 2D area and vast 3D extent of the Hubble eXtreme Deep Field:

CREDIT: NASA, ESA, and G. Bacon, F. Summers, and Z. Levay (STScI)

Astronomers call such long exposures “deep” because fainter objects tend to be farther away, hence, a longer exposure sees deeper into the universe. The new deep field is the latest in a line extending back to the original Hubble Deep Field (HDF), released in 1996. That breakthrough observation was followed by the HDF South (1998), the Great Observatories Origins Deep Survey (2003), the Hubble Ultra Deep Field (HUDF, 2004), and the HUDF09 (2009).

The Hubble eXtreme Deep Field builds upon the HUFD09 image by adding all Hubble observations that, done for a variety of research programs, cover the HUDF field on the sky. In that sense, it should perhaps be called the HUDF12, but that’s less catchy and trendy than calling it “extreme.”

However, calling it extreme does have its perils as well. It implies that Hubble will never exceed it, which is wrong. Observations continue to be taken and two programs in particular will add significantly to the data set. One will continue to add to the infrared portion of the image, as was the major improvements seen in the 2009 and 2012 deep field images. Another will flesh out the ultraviolet observations in a program one colleague jokingly referred to as “deep purple.” (Younger readers should look that up on Wikipedia while older readers immediately start humming the intro guitar riffs to “Smoke on the Water.”)

Will there ever be a “deepest” image? The answer can be both “no” and “yes.”

No, there will just be a series of “deepest yet” images, as astronomers will continually build new instruments and new telescopes enabling better observations. Deep fields with the James Webb Space Telescope are already eagerly awaited.

But also “yes,” if one thinks in terms of depth in space. As we look farther out in space and further back in time, we will get to a point before the first stars and galaxies formed. Earlier than about 100-200 million years after the Big Bang, there may be no light to see. We can, in the not-too-distant future, reach the edge of the observable universe.

Whoa. Now that’s deep.

No, Pluto is not ready for its close up, thank you.

Oh, Pluto. Beloved Pluto. The endearing, scrappy runt of our solar system litter, demoted but never defeated. We heart you, you crazy little Kuiper Belt Object, with your icy surface and newfound moons and multiple references to Disney films, what with Mickey Mouse’s dog and now the dwarf planet thing. Hi-ho, Pluto. Hi-ho.

So today we’re going to discuss a question I encounter on occasion. “Hey,” it goes, roughly, “How come we can see all this detail in a galaxy 46 million light-years away, but your pictures of Pluto look like someone airbrushed a basketball and photographed it through a Vaseline lens at the bottom of a swimming pool? Pluto’s right next door, while this galaxy is clearly at least as far away as the mall.”

Well, aggrieved person suspiciously intent on invading Pluto’s privacy, first understand that these images are actually really neat. This is the most detailed view ever of the entire surface of Pluto. You’re watching the seasons occur on an object so far away that it takes light from the Sun over five hours to reach it. We’re honestly a little hurt. Do you know how much effort that took? How much manpower? Do you think it’s easy to smear that much Vaseline on a lens in space? It is not.

You are right, though – Hubble’s pictures of Pluto do lack the detail people have come to expect from the telescope. Basically, it’s an issue of size. To understand it, you have to understand something called “angular resolution,” which – where are you going? Get back here right now, Pluto e-mailer, and listen while I explain angular resolution to you in excruciating detail! That’s right. We’re all in this together, now.

So, angular resolution. Draw two lines on a piece of paper and have a friend hold that paper up and start to walk backwards. Eventually, you’ll only see one line. That’s angular resolution in action – the ability of a picture-taking device – in this case, your eye – to distinguish between details. If you use a much bigger piece of paper, and draw the lines farther apart, your friend will get farther before you stop seeing two distinct lines. Both size and distance matter when it comes to angular resolution.

Angular resolution is a set thing – for eyes, for cameras, and for telescopes. The human eye has an angular resolution of about one arcminute. Hubble has an angular resolution of .05 arcseconds. That’s good enough to stand on the East Coast of the US and distinguish between lines spaced about three feet apart on a piece of paper that your friend is holding up on the West Coast. Also, that’s one really good friend you have there. Does he owe you money, or a kidney, or something?

Now, galaxies are huge. When Hubble looks at a galaxy, it’s observing a collection of immense objects at incredible distances from one another. (Even then, you’re usually seeing clusters of stars, not individual stars in these galaxies – Andromeda is about the farthest galaxy in which Hubble can actually resolve individual stars.) The beautiful spiral galaxy NGC 2841 is a bit over two arcminutes in size.

Little Pluto? He’s about .06 to one arcseconds wide in the sky.

The angular resolution of a telescope, just like the angular resolution of your eyes, is fixed. Hubble is resolving both the galaxy and Pluto the exact same way. But one has a lot more space and size to work with than the other.

These images of Pluto are painstakingly compiled from lots of Hubble data with the help of years of computer processing. As one astronomer put it, they’re really maps, not pictures.

But it’s not over, saddened, would-be Pluto observer. You’ve got 2015 to look forward to, when the New Horizons spacecraft will complete its decade-long, 3-billion-mile journey to the smallest sort-of member of the solar system and give us a spectacular, up-close view of this Kuiper Belt object … for six months. And then it’s back to fuzzy basketballs as seen through multiple layers of gauze on a foggy day with debilitating nearsightedness.

So time will be, as they say, of the essence. And that’s when those seemingly dull Hubble maps will prove their worth, helping astronomers decide the most interesting areas on Pluto for the probe to target while it can.

The Whirlpool Galaxy

When I was under the velvet-black skies of western Texas a few months ago, I had a magnificent view of the star-studded bulge of our galaxy in the direction of the summer constellation Sagittarius.

How many advanced alien civilizations might be in this crowded hub of the Milky Way, I pondered? The problem is that we are embedded in a thick forest of stars, and identifying the location of an extraterrestrial civilization – one that’s attempting to contact us – is the proverbial needle-in-a-haystack search, as the SETI scientists always say.

So instead of looking for signals, perhaps the way to find evidence of E.T. is to scrutinize the physical evidence in a neighboring “forest,” or rather nearby galaxy.

Because even the nearest galaxies are millions of light-years away, any idea of communicating with these aliens is unfeasible. Our observations would be made for purely identifying archeological evidence of the actions of a civilization.

For this to work you would have to look at the tallest trees in that forest, i.e. engineering activities on such a large scale they give an anomalous appearance to the galaxy that cannot be explained by known astronomical processes. The features would instead be the handiwork of super-duper civilizations that are leaving their ecological imprint on the galaxy at a mega-scale.

In 1964, the Soviet astronomer Nikolai Kardeschev hypothesized such extraterrestrial civilizations as Type II. They would surpass our energy production capabilities by a factor of approximately 10 billion. How? By capturing the total energy output of their parent star.

In the early 1960s, physicist Freeman Dyson proposed that a shell could be built around a star to trap much of its energy. The shell would be fabricated from dismantling a planet about the mass of Jupiter.

This so-called “Dyson sphere” is legendary, and there have even been searches for the signature of such artifacts in astronomical infrared databases. The problem is that a star enshrouded in dust would look pretty much like a Dyson sphere. In a survey of 250,000 infrared sky sources cataloged in the 1970s, 17 “quasi-plausible” Dyson sphere signatures came up, according to Richard Carrigan of Fermilab.

It’s imaginable that a super-civilization would begin a wave of colonization that spread out to neighboring solar type stars from its home base. Each offshoot would “astro-form” the colonized planetary system by constructing a Dyson sphere around the host star.

Carrigan envisions seeing “Dyson bubble” in nearby galaxies. These would be clusters of Dyson spheres that enclosed a grouping of stars colonized by a Type II Kardeschev civilization.  The logic is that after you’ve built a backyard fence, you can start to conceptualize building the Great Wall of China and still hope to gain perspective on the process, Carrigan says.

These Dyson bubbles would be detected as anomalous dark voids in a galaxy’s disk. When these voids were observed in infrared light they would glow brightly with the heat radiation from the surfaces of Dyson spheres. This would show that they are not simply voids where solar-type stars are conspicuously missing.

The Hubble Space Telescope is conducting a multi-year survey across a swath of the neighboring Andromeda galaxy. The images are filled with so many resolved stars that they look like grains of sand on a beach. This could make an excellent citizen science project, to scour the Andromeda fields for anomalous-looking regions.

The magnificent face-on Whirlpool galaxy, M51, is an ideal place to go looking for Dyson bubbles. Hubble has photographed the entire galaxy down to a resolution of roughly 15 light-years across.  Present Hubble and Spitzer Space Telescope infrared photos of the Whirlpool reveal the typical galaxy’s intricate cobweb tracing in dusty filaments.

However, a rough qualitative estimate by Carrigan suggests that there are no unexplained bubbles or voids in M51. This analysis is complicated by the fact that the infrared light skeletal pattern of a spiral galaxy pattern itself is shaped by voids.

Gigantic elliptical galaxies, which are completely devoid of light-blocking dust, would look very odd indeed if dark voids were detected. However, the nearest ellipticals are 60 million light-years away and so would require a space telescope much larger than Hubble to yield enough resolution to detect anomalies.

An apparent lack of any evidence for large-scale artifacts in galaxies as old as ours begins to set an upper limit on just how technologically advanced alien civilizations can evolve.

Kardeschev hypothesized about Type III civilizations that would harness the entire energy of a galaxy. The observational evidence for astro-engineering an entire galaxy is lacking, and so it’s fair to say that Type III civilizations just don’t exist at all – or at least not yet.

The universe has had 12 billion years to evolve a Type II or Type III civilization. If there’s no obvious archeological evidence, than maybe intelligent beings don’t evolve all that far beyond our projected capabilities of perhaps mega-engineering on the scale of a single solar system.

Maybe extraterrestrials simply don’t have the motivation, know-how, or the budget.

Jupiter could be the next test subject for analyzing light from a Venus transit.

My blog post of May 25, 2012 was titled “Examining Venus in a Lunar Mirror.” In that piece, I described how Hubble would attempt to observe the transit of Venus on June 5, 2012.

The idea is that, since Hubble cannot directly observe the Sun, one could look at the Sun’s light reflected off of the Moon. A detailed analysis might be able to separate out the signature of light that passed through Venus’ atmosphere. The observation would be a proxy for studying the atmospheres of extrasolar planets that happen to transit their star from our point of view. Venus, with a known atmosphere, could serve as calibration for the unknown atmospheres of extrasolar planets.

Sad to say, the Hubble observations were a failure. Not every science experiment goes as planned. Well, actually, this observation went as planned, but the planning was incorrect. A miscalculation in positions meant that the observation did not capture what had been intended.

But science is an enterprise where learning from failure is not just possible, it is one of the main methods of advancing the field. For all the triumphs and breakthroughs that are celebrated, there are a thousand times more investigations that uncovered modest, incomplete, or dead-end results. That work invariably builds the foundation and shapes the blueprints for the eventual discovery.

In this case, the lesson is to think bigger: Don’t just take our Earth-bound perspective, consider things from a solar system perspective. The next transit of Venus as seen from Earth will be in December 2117, but the next Venus transit visible in our solar system will be on September 20, 2012 – seen from Jupiter.

A proposal has been put forward for Hubble to observe Jupiter, both before and during this transit, to perform a study of the Venusian atmosphere in reflected light similar to Hubble’s Venus transit Moon observations.

Perhaps more exciting, Earth itself will transit the Sun as seen from Jupiter on January 5, 2014. What could be a better test of looking for Earth-like planets elsewhere than to study our own planet in an analogous fashion? Mirror, mirror in the sky, Hubble watches Jupiter as Earth passes by.

Opportunity arises from understanding one’s mistakes. It is a great lesson in science and in all of life’s pursuits.

The light from our neighbor Andromeda is 2.5 million years old. CREDIT: T. Rector and B. Wolpa (NOAO/AURA/NSF)

Hi everyone. My name is Tracy Vogel, and I’m a writer and editor for the Office of Public Outreach at the Space Telescope Science Institute. I’m also the person who answers e-mail for HubbleSite. You know how you shoot off an e-mail to HubbleSite and expect it to get answered by some kind of automated robot? That’s me! I’m the robot! Hi! It’s very exciting to meet you all, and to finally be able to point out that Hubble, a non-sentient telescope floating through space, neither needs nor possesses a LinkedIn account. Though I’m sure it would thank you all for the many, many, many gracious invitations.

Unlike the other members of this blog, I’m not an astronomer. But I do spend a lot of time asking them questions. “Can Hubble be seen with the naked eye?” “Do we know the age of the universe?” “Are we scheduled to observe that giant invisible death planet that’s going to crash into the Moon?” (The answers are, respectively: “Yes,” “13.7 billion years,” and “Can I see your employee ID, again?”)

Why do I need to know these things? Well, it’s probably my unquenchable thirst for knowledge. Or my massive, overflowing inbox of e-mail queries. One of those! And since the questions we get are actually quite interesting, and at least a handful are not written in all-caps by people who appear to be typing by gnawing on the keyboard, we thought we’d share them with you. To elucidate you, the public, with your inquisitive minds and your curiosity-driven missives and your obvious homework questions that you’re clearly hoping I will do for you so you can get back to playing Mario Kart. (Yes, of course all the answers are “The Crab Nebula,” hopefulsixthgrader@gmail.com! You can trust me! I work for science.)

Anyway! Occasionally I’ll be jumping in on this blog to discuss some of our more common or uncommon questions, or Hubble news of note. Because they are paying me, and our public demands it. In between bouts of Mario Kart.

Today’s question is one we get fairly often: You keep talking about seeing galaxies in the past. How does that work, anyway? The past is, well, past — thus the name. How does having a telescope let you see something that happened millions of years ago?

To understand this, you first need to know something about how a telescope works. Telescopes provide you with a bigger lens than the ones you have in your eyes. Because it’s bigger, it can capture more and much fainter light than your eyes can on their own. But telescopes don’t reach out into space — they stay right here (or 353 miles above here, in Hubble’s case) and wait for the light to hit.

Light moves. It moves extremely fast — at about 186,000 miles per second — so it looks instantaneous when you flip a switch, but it takes time to travel across the vast distances of space. Light from the Moon takes about 1.3 seconds to get to Earth, so when you look up at the sky, you see the Moon as it was over a second ago. Light from the Sun takes 500 seconds to reach us; the sunlight hitting your face is over eight minutes old.

Other galaxies are so far away that we actually measure the distance to them in the time it takes light from them to reach us — the “light-year.”

The nearest large galaxy, Andromeda, is 2.5 million light-years away, thus its light takes 2.5 million years to reach us. When you look at Andromeda, you’re seeing ancient history. And if you lived in the Andromeda galaxy, and you were looking at the Milky Way right now, you’d be seeing this galaxy as it was 2.5 million years ago. Wave hello to Earth’s Glyptodonts, Andromedeans! They won’t wave back, as they’re deeply, extremely, enthusiastically extinct, but that’s no reason to be rude. Upon further reflection, it seems like a good reason to be extra polite. A moment of respectful silence, everyone, for the Glyptodonts. I think we can all agree that the world would be a better place today if it still had Volkswagen-sized armadillos. Thank you.

Anyway. The point is that the farther away an object is the longer it takes for the light to reach us. So the light from the most distant objects we can see started traveling billions of years ago, when the universe itself was young.

So that’s why Hubble can look at deep space and see objects as they were far in the past. Doesn’t seem quite so odd when you realize you’re doing it yourself, every time you look at the stars, does it?

She spends her free time doing extraordinarily interesting things, way more interesting than you could believe, in fact she won’t even get into them because they would make you terribly jealous and that would be wrong. They probably involve international traveling, skydiving and some sort of animal wrangling, possibly of platypuses. Platypi? Or koalas.

Send her your Hubble or Webb questions here: http://hubblesite.org/about_us/contact_us

Artist's concept of Pluto and its moon Charon. (NASA)

This month the infamous “un-planet” Pluto grabbed science headlines with the report of yet another moon whirling around it.

The Hubble Space Telescope discovery brings the tally of icy moons orbiting Pluto to five.

Or is it really four?

A reader wrote me to make the case that Pluto really has only four moons (all discovered by Hubble over the past seven years). He argued that the largest moon in the system, Charon (found in 1978), is really a planet in its own right.

Why? Because Charon is 12 percent the mass of Pluto. That may not seem like much, but our Moon is only .01 percent the mass of Earth.

The consequence is that Pluto and Charon pivot like a waltzing pair of ice skaters around a center of mass.  So do the Earth and Moon, but the center of mass, or barycenter, is inside Earth’s radius. However, alien astronomers watching Earth transiting the Sun would note the passage of our Moon as well. They might catalog Earth as a “double planet.”

That was the reader’s point. Pluto’s four outer satellites don’t really orbit the dwarf planet; they follow Keplerian orbits around the system’s center of mass, which lies between Pluto and Charon. Pluto and Charon complete one pivot around each other every 6.3 days.

When we see a pair of stars twirl around a barycenter, they are classified as binary stars. Binary systems account for at least half of the stars in our galaxy. Binary stars are born through the fragmentation of the collapsing nebula that condensed to form them.

Dozens of binary asteroids have been cataloged since 1993. They may form though the splitting of a single, fragile parent body.

So why not have binary planets too?

The popular theory is that a collision between Pluto and another icy dwarf planet spawned Charon and the other moons. A similar sort of collision has been theorized for the birth of Earth’s moon 4.4 billion years ago, though this theory has recently been questioned.

Other binary planets might be out there, though none have been uncovered in numerous surveys. They may be exceedingly rare outside of debris belts like our asteroid belt and Pluto’s Kupier belt.

Nevertheless, there could be binary planets out there that are inhabitable. The consequences would be extraordinary. The planet where intelligent life first arose would dominate the companion planet. There would be a “space race” to colonize the companion world – and no doubt the winners would subjugate whatever was living there. Travel and trade between the two worlds would become commonplace.

In 2006, the International Astronomical Union (IAU) initially considered characterizing Pluto-Charon as a binary planet.  But in all their hissy-fit fuss over what to call Pluto, Charon was simply left as a satellite of Pluto.

The IAU missed a great opportunity here to break new ground in our classification of oddball planetary bodies.

A young boy watches himself on the Webb Telescope booth’s infrared camera at the Intrepid Museum’s Space Fest.

Imagine flying in an airship that weighed some 150,000 pounds, could land like an airplane but needed a rocket to launch, and could fly both in and beyond Earth’s atmosphere. You’d belong to a select group of only 355 individuals who have ever flown on such a vehicle: NASA’s Space Shuttle.

Columbia, Challenger, Discovery, Endeavour, and Atlantis — between 1981 and 2011, these five Space Shuttles ferried the 355 astronauts and a huge number of satellites into low-Earth orbit. These shuttles orbited the Earth at altitudes of just a few hundred miles, typically; think Florida or Colorado standing up vertically. But they went round and round more than 21,000 times in total, racking up more than half a billion miles — the distance between the Sun and Jupiter. Thanks to the shuttle, we’ve built the International Space Station, seen astronauts perform feats of daring and delicateness in free fall, and launched and serviced the Hubble Space Telescope.

Another (actually, the first) shuttle, Enterprise, never flew in space but was the prototype used to prove that the vehicle could glide and land successfully, and to test how well the shuttle carrier aircraft worked in concert.

The shuttle era is now in the past; NASA is focusing on newer and more advanced vehicles to launch scientific satellites and carry humans to nearby asteroids and Mars. The retired shuttles are (or will be) on permanent public display at a variety of locations nationwide: Discovery at the Smithsonian National Air & Space Museum’s Udvar-Hazy Center near the US capital, Enterprise at the Intrepid Sea, Air & Space Museum in New York City, Endeavour at the California Science Center in Los Angeles, Atlantis at the Kennedy Space Center Visitor Complex in Florida. Now, the American public and visitors to these cities can get up close and personal with the orbiters, and experience something of their remarkable history.

Enterprise had been on display at the Udvar-Hazy Center, and was transported to New York City in early summer 2012. The Intrepid Museum crafted a protective pavilion on its flight deck for this pioneering spacecraft, and plans to build a more permanent exhibit hall for it. It is truly moving to behold one incredible machine resting atop another, in the company of dozens of naval aircraft, all carrying historic legacies, and with the New York skyline as their backdrop.

To celebrate the shuttle pavilion’s opening to the public, the Intrepid Museum held a “space fest” between July 19 and July 22, 2012. And NASA was there to join the celebration. Dozens of exhibit booths showcased NASA’s aeronautics, space exploration and science missions and programs. There were models of the Mars mission Curiosity (that landed on the red planet just last week!), solar telescopes to safely view our nearest and dearest star, space suits in which people posed for pictures, and other cool exhibits. And thousands of museum visitors mobbed these exhibits, staying to chat excitedly about science and space exploration.

Several of my colleagues from STScI and NASA Goddard staffed the James Webb Space Telescope booth. We had a 1:20 scale model of the telescope. We showed videos of its mirrors and instruments being built, explained how the solar panels would unfold in space, and discussed the cool science to be done by Webb. Since Webb is an infrared (IR) telescope, we had set up a commercial IR camera and large display, so that visitors could see themselves in this “invisible light.”

All warm, dense bodies emit electromagnetic radiation. The temperature of the body determines the color or, equivalently, the wavelength of the radiation. Humans and other land animals emit IR radiation, not the visible light that our eyes can see. IR light has wavelengths that are too long for our eyes to detect, but specialized IR cameras or some regular digital cameras equipped with long-wavelength-sensitive CCDs can capture our thermal emission and show us our “temperature map” in false color.

Our IR camera at the Space Fest was a big hit. Visitors walking by stopped in their tracks to see familiar yet strangely colored versions of themselves on the monitor. They exclaimed about actually seeing — rather than feeling — how cold their noses or hands were in contrast to the tops of their heads. They rubbed their hands and saw the resulting warmth show up as a brighter glow on the IR camera. We offered them fun activities to try: hold an ice cube and see how that changed what their hands looked like; blow-dry their hair and make it seem like it was aflame. Mothers brought their kids, and kids dragged their parents, to “see” themselves in a new light. Visitor who spoke no English exchanged delighted grins and connected with us without needing words. And all this despite the overcast skies and cold rain that threatened to dampen the first two days of the Space Fest.

Outreach events like this take a lot of time and effort to organize. It’s all made worthwhile by the excitement people find in connecting with each other and with the wonders of the universe through the incredible journey of exploration that is science.

However, there is still one great unknown, and it was emphasized in a discussion by the original SETI pioneer, Frank Drake. About five decades ago, he identified seven factors that, taken together, can help estimate how many technological civilizations should exist in our galaxy. He noted that significant progress had been made on six of the factors, while scientists are powerless to do anything about the seventh.

The great unknown is time. Once a technological civilization is established, how long does it last?

Stars have been continually forming in our galaxy for billions of years. Life on Earth took another four and a half billion years to develop into a technological civilization. Yet we have had that technology for only about 100 years.

If another civilization developed around a nearby star millions or billions of years ago, would they still be there for us to discover? We have no evidence that civilizations can survive for the billion-year timescales that are typical of stars and the development of life.

In fact, the best chance we have for improving our estimate of this factor would be to actually discover an extra-terrestrial civilization. Then, we could finally have a second data point on how long such civilizations can last. It is one of those things where patience is not just a virtue, it is the only possibly response.

Only time will tell.