Speaking of Hubble...

Archive: Frank Summers

Gazing Deeply into the Universe

October 8, 2012 by Frank Summers
Hubble’s eXtreme Deep Field

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.

Mirror, Mirror in the Sky

September 7, 2012 by Frank Summers
Jupiter could be the next test subject for analyzing light from a Venus transit.

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.

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.

Not in a Billion Years

July 20, 2012 by Frank Summers
After the Milky Way-Andromeda merger, our Sun will likely be tossed into a looping orbit around the newly formed elliptical galaxy.

After the Milky Way-Andromeda merger, our Sun will likely be tossed into a looping orbit around the newly formed elliptical galaxy.

In the recent Hubble press release about the collision between our Milky Way galaxy and the Andromeda galaxy, we provided some artistic illustrations of what a future night sky might look like. It shows the fantastic sights as Andromeda approaches, smashes through, and eventually merges with our galaxy.

Although it may seem like splitting hairs, I note that we specifically did not say that those illustrations show what Earth’s night sky would look like. There are three reasons for this.

First, those illustrations were motivated by views from a computer simulation. The viewpoint inside the simulation was held fixed in space at the Sun’s current location relative to the center of the galaxy. Though the Sun continually orbits the core of the Milky Way, a fixed location provided a more easily understandable sequence of images.

Second, the Sun’s orbit in the galaxy will probably change greatly during the collision. Our star could get flung far into the outskirts of the Milky Way, drop deep into the core of the galaxy, or do both on a spirograph-like orbit. Almost all scenarios greatly change our night-sky view.

Third, and most important, while Earth should still orbit the Sun in 4 billion years, it probably won’t be habitable. Our Sun is slowly getting hotter as it ages. According to calculations, in about 3 billion years the Sun will be hot enough that Earth’s oceans will evaporate and its atmosphere will escape. Human life on the surface of our planet will not be feasible without planet-scale engineering efforts.

The illustrations show what a night sky might look like, but the view seen by a future human civilization is guaranteed to be different. Still if our species survives to see it, it will be awesome to have two galaxies stretched across the sky. Although, as an astronomer, I can’t help but imagine how confusing it might be to detangle the star and galaxy motions.

When Galaxies Collide; Stars Don’t

June 28, 2012 by Frank Summers
Arp 148 is a unique snapshot of an ongoing collision.

Arp 148 is a unique snapshot of an ongoing collision.

In a recent blog post, I discussed the collision between our Milky Way galaxy and the Andromeda galaxy. In about four billion years, the two vast, spiral shapes will combine and transform into a single elliptical galaxy via a powerful gravitational smash-up.

News of the awesome collision prompted many to ask about what happens to the stars within the galaxies. In particular, what might happen to our Sun and the planets around it.

The good news is that when galaxies collide, the stars inside them won’t crash together.

To understand why, one has to recognize just how far apart the stars are. It’s easiest to explain with a scale model.

Suppose the Sun were the size of a baseball. I live in Baltimore, so let’s imagine this baseball is located at home plate in Oriole Stadium.

One of the stars nearest our Sun is Alpha Centauri. Let’s also shrink that star down to a baseball for our scale model. The question is: where would the Alpha Cen baseball be located?

It would not be in the infield, or the outfield, or anywhere in the ballpark. It would not be in the city of Baltimore or even in the state of Maryland. For a correct scale model, the Alpha Cen baseball would be about 1,300 miles and many states away — in Houston, Texas.

One baseball in Camden Yards and one baseball in the Astrodome — that’s the relative size and separation of the stars in our part of the galaxy. You can see that there is a lot of space between Baltimore and Houston for other baseballs to pass through.

Hence when galaxies collide, the stars stream past each other at vast separations. The orbit of our Sun within the combined galaxy may change greatly, but the orbits of the planets around the Sun will not be affected.

One can rest easy knowing that our solar system will survive the great collision between the Milky Way and Andromeda. However, that doesn’t mean that the billion-year future of Earth is all rosy. There are other factors that will greatly alter our planet. I’ll discuss those in my next posting.

Crash of the Titans

May 31, 2012 by Frank Summers
ILLUSTRATION CREDIT: NASA, ESA, Z. Levay and R. van der Marel (STScI), and A. Mellinger

ILLUSTRATION CREDIT: NASA, ESA, Z. Levay and R. van der Marel (STScI), and A. Mellinger

Imagine what goes through the mind of a baseball batter as he stares down a speeding pitch. The baseball is hurtling toward him, but difference between a strike and a ball depends on precisely gauging the amount of sideways motion. He’ll want to swing for the fences if it’s out over the plate, or jump back out the box if it’s headed for his ear.

Astronomers have been pondering a similar situation for about a hundred years. We can easily measure whether the neighboring Andromeda galaxy is moving toward or away from us (we call this “radial” motion). The result, known to Edwin Hubble in the 1920s, is that Andromeda is approaching our Milky Way galaxy at the tremendous speed of more than 250,000 miles per hour.

However, it is extremely difficult to measure the sideways (or “tangential”) motion of a galaxy. We have been left wondering: what is Andromeda’s full trajectory? Will the two galaxies simply pass by each other like cars on opposite sides of an interstate highway, or will there be a colossal pileup involving hundreds of billions stars in each galaxy?

It has taken Hubble’s namesake telescope, with its exquisite resolution, and some innovative imaging and computational measurement techniques to finally answer this question. By measuring minute shifts in the stars of Andromeda over the course of about a decade of observations, we now know that Andromeda has very little sideways motion. It is heading straight for the Milky Way, and, unlike the baseball batter, our galaxy can’t get out of the way.

VISUALIZATION: NASA, ESA, and F. Summers (STScI)
SIMULATION: NASA, ESA, G. Besla (Columbia University), and R. van der Marel (STScI)

The two galaxies have been destined by gravity to crash together in about four billion years. Their thin and beautiful spiral disks will become warped, stretched, and distorted beyond recognition. The centers of the galaxies will smash through one another not just once, but several times as the galaxies merge. Eventually, about six billion years from now, the two spirals will become one elliptical galaxy, mixed together for all eternity.

Our visualization of this galactic gravitational dance is the first scientific look into the far-flung future of our galaxy. Our news release features artistic visions of what the view might be from within the Milky Way during the collision. The stars and the band of the Milky Way across the night sky seem static and constant on human time scales. But taking an astronomer’s perspective, and looking forward billions of years, they have quite a dynamic future ahead of them.

Examining Venus in a Lunar Mirror

May 25, 2012 by Frank Summers
blog_2012_05_25

Hubble can't look at the Sun directly, so it will observe the Venus transit with sunlight reflected off the Moon.

On June 5, 2012, the last Transit of Venus will happen in your lifetime. Unless, of course, you plan on living until December 2117 to catch the next one. Because it is the “last chance of a lifetime,” folks are clamoring about when and how to observe it. But I’ve found that many people have even more basic questions like “What exactly is happening?” “Why should I care?” and “Won’t Hubble get the pretty pictures for us?”

First off, the event is that the planet Venus will pass directly between Earth and the Sun. For several hours, Venus will appear as a dark dot moving across the Sun’s brilliant face. The precise alignment required for such a transit happens very rarely: pairs of Venus transits are separated by eight years, with 105.5- or 121.5-year separations between pairs. The first of this current pair occurred in 2004. The 2012 transit of Venus is only the eighth since the telescope was invented in 1609.

Historically, Venus transits were very important in measuring the precise distance to the Sun. A single measurement of a transit provides the relative sizes and distances to Venus and the Sun. Multiple measurements from multiple places on Earth enable astronomers to triangulate the true distance to the Sun. In the 1700s and 1800s, no other astronomical observation could provide this measurement, and grand expeditions were funded to observe Venus transits.

Today, we have radar measurements of the distance to Venus, so transits are not the unique opportunity they once were. For Hubble, however, the 2012 transit of Venus will be a unique opportunity of a totally different dimension.

Exciting discoveries can be made by studying an extrasolar planet that transits in front of its star. Some of the star’s light passes through the planet’s atmosphere, and we can determine the composition of that atmosphere. The same argument applies to the transit of Venus. However, since we know the composition of Venus’ atmosphere, observing its transit can provide an invaluable calibration and substantiation of the techniques used on extrasolar planets.

But, Hubble never looks at the Sun. Our star’s dazzling light would irreparably damage the telescope’s optics. Instead, Hubble will use the Moon as a giant mirror, studying its reflected sunlight to glean information about the Venus transit. It is a difficult observation, but one that mimics some of the complexity of observing extrasolar planets.

Who would have thought that the path to searching for habitable planets in the universe would involve examining Venus in a lunar mirror?

Cinematic Scientific Visualizations

May 9, 2012 by Frank Summers
A sequence from "Hubble 3D" takes us on a journey to the heart of the orion nebula. CREDIT: "Hubble 3D" © 2010 Warner Bros. Courtesy Warner Bros. and IMAX Corporation

In this frame from the movie "Hubble 3D," the viewer enters the central region of the Orion Nebula. CREDIT: "Hubble 3D" © 2010 Warner Bros. Courtesy Warner Bros. and IMAX Corporation

Within our Office of Public Outreach, I lead a team that produces three-dimensional visualizations based on Hubble images and data. Most notably, our team worked on the IMAX filmHubble 3D.” In collaboration with our partners at the National Center for Supercomputing Applications (NCSA) and the Spitzer Science Center, we worked on 12 minutes of scientific visualizations for the movie.

At a conference last week, I was invited to speak about our work on the project. I began with a reference to the old adage of “truth and beauty” as twin goals of artistry that both complement and conflict with each other. I noted that our documentary work must grow out of the truth side, while commercial (and fictional) films develop more from the beauty side. In fact, the incredible sophistication of movie computer graphics has raised audience expectations to a level that make standard scientific presentations look antiquated.

Taking Hubble to the big screen required many months of exacting work. I detailed the transformation of raw data into images, the variety of methods employed to create three-dimensional computer models, and the intensive computational requirements for these giant-screen, stereo 3D visualizations. I wanted to emphasize both the scientific underpinnings as well as the artistic effort necessary to produce the shots and sequences.

After my talk, one audience member sheepishly admitted that, when he saw the film, he had assumed the all of the sequences were fantasy Hollywood computer graphics. I was at first taken aback that our painstaking scientific basis was not recognized, but later I felt complemented that the sophistication of our work had risen enough to be considered “too good to be true.”

Donna Cox, my counterpart at NCSA, and I developed the phrase “cinematic scientific visualizations” to describe what our teams strive to produce. In that pursuit, we use not only the same software as used in astronomy research, but also the same software used in producing Hollywood blockbusters. Our goal is an elusive balance of accuracy and aesthetics.

While our artistry is well above the standard of science, we have neither the money, the manpower, nor the time to achieve the amazing complexity and detail that Hollywood routinely produces. In the end, however, that doesn’t matter.

The connection back to the underlying science is the crucial element that elevates our work. The knowledge that there is truth behind the beauty is what makes Hubble imagery all that more powerful.

Cosmic Puzzles

April 26, 2012 by Frank Summers

cosmic puzzleSome folks assume that professional astronomers all had telescopes when they were kids; that they grew up memorizing constellations and facts about planets, stars, and galaxies; and that they got white lab coats for their ninth birthdays.

None of those are true about me. I got a bicycle for my ninth birthday, and I’ve never owned either a white lab coat or a telescope (unless binoculars count).

The reason I became an astronomer is that I am obsessive about solving puzzles. As a child in the 1970s, I loved playing with the Soma cube puzzle. When the Rubik’s Cube went on sale in 1980, I bought one the first day I heard about it. I twiddled, solved, and created patterns on it for many moons. I own every size cube up to a 7×7x7 — that’s seven squares in each row — including a 1×1x1 that a friend made for me, and dozens of other 3D rotating, flipping, and/or sliding puzzles.

Beyond those physical manipulation puzzles, I also love the intellectual challenge that many math students fear most: word problems. To me, equations are only really interesting when applied to a situation. Give me a description, let me deduce both the method and the solution, and I‘m hooked. In addition to baseball, I played at recreational math. I felt I lost a bit of my childhood when Martin Gardner, math and science writer best known for his Scientific American math puzzles, passed away a couple years ago.

So I came to astrophysics in a sideways fashion. I was brilliant at math, and the best math problems came from physics. As I progressed through college physics, the most interesting situations were in astronomy. What could be a greater puzzling challenge than to deduce all the physics of a situation trillions of miles away simply by examining the light it emits? And the answers described possibilities not only unheard of, but also impossible to reproduce here on Earth.

When speaking to students, I tell them it’s OK not to know what you want to be when you grow up. At one time, I dreamt of being a baseball pitcher. My experience says that if you work hard and follow your passion, you never know where it might take you.

It may say “astrophysicist” on my business cards, but really, I’m just a cosmic puzzle junkie.