Speaking of Hubble...

Archive: August 2012

Telescopes as Time Machines

August 31, 2012 by Tracy Vogel
Credit: T. Rector and B. Wolpa (NOAO/AURA/NSF)

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?

Is Charon a Moon of Pluto Or a Binary Planet?

August 23, 2012 by Ray Villard
Artist's concept of Pluto and its moon Charon. (NASA)

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 Day of Celebration and Inspiration

August 16, 2012 by Mangala Sharma
A young boy watches himself on the Webb Telescope booth’s infrared camera at the Intrepid Museum’s Space Fest.

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.

Life’s Great Unknown

August 9, 2012 by Frank Summers

NewCenter: Artist's Concept of Extrasolar Planet's Hazy AtmosphereIn June 2012, I was a speaker at SETICon, a convention about the search for extra-terrestrial intelligence and related space topics. A slew of presentations detailed just how far we have come in finding and characterizing planets around other stars. Given that telescopes like Kepler are now able to detect Earth-size planets, and telescopes like Hubble have been able to detect specific gases in some planet atmospheres, the prospects for discovering signs of life are more enticing than ever.

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.

Hubble in Hollywood

August 2, 2012 by Frank Summers
"Hubble 3D" Director Toni Myers (left) and Dr. Frank Summers at the Academy of Motion Picture Arts and Sciences. CREDIT: AMPAS

"Hubble 3D" director Toni Myers (left) and Dr. Frank Summers at the Academy of Motion Picture Arts and Sciences (AMPAS). CREDIT: AMPAS

On July 10, 2012, I got to say those famous words of Oscar recipients: “I would like to thank the Academy …” Of course, my thanks were not for an award, but rather for being invited to participate in a panel discussion at the Academy of Motion Picture Arts and Sciences in Hollywood. In the theater where they announce the nominees for the Academy awards, and flanked by giant golden statuettes, we held a public presentation on NASA and the movies called “Capturing the Final Frontier.”

A series of four panels discussed the NASA involvement in two documentary films and two feature films. I discussed our work on the IMAX film “Hubble 3D” along with the director Toni Myers. The other movies showcased were “Roving Mars,” “Transformers: Dark of the Moon,” and “Mission to Mars.” Panelists included producers, directors, visual effects artists, and NASA officials. I was the sole astrophysicist, and I think the Academy folks were pleasantly surprised that I could speak with passion and some eloquence about an artistic topic.

We spoke in front of a sold-out, enthusiastic crowd, and the evening went extremely well. The audience was treated to some great clips of astronomical and space sequences as well as behind-the-scenes looks into how they were made. Many panelists emphasized that the use of real data from NASA missions is crucial to lend authenticity, even if the story is pure fiction.

That point underscored for me the great value of the public domain. NASA missions are paid for with public dollars, and the fruits of those missions are available to all. Here at HubbleSite, you will find every pixel of the highest resolution available for our press release images. The Hubble archive is publicly accessible, as are those of other NASA space telescopes, space missions, and manned spaceflight. Action films don’t need to accurately re-create a site on the Moon, but with the copious Apollo images, they can and do.

Looking back, I suppose I should have been more nervous in front of that prestigious crowd. But I so much enjoy discussing our scientific visualization work, I didn’t really think about the august setting. Actually, the most unusual part of the event occurred right at the beginning. Upon arrival, I and the other participants were ushered in front of an Academy-logo adorned backdrop while several paparazzi-like cameras flashed for a minute or two. The next day, I found photos of myself on one of those gossip- and glamour-type web sites. That experience was definitely more than a bit surreal for an astrophysicist.