Faint Worlds On the Far Horizon

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Faintest distant galaxy ever detected, formed only 400 million years after the Big Bang. NASA, ESA, and L. Infante (Pontificia Universidad Catolica de Chile)
Faintest distant galaxy ever detected, formed only 400 million years after the Big Bang. NASA, ESA, and L. Infante (Pontificia Universidad Catolica de Chile)

For thinking about the enormity of the canvas of potential suns and exoplanets, I find images like this and what they tell us to be an awkward combination of fascinating and daunting.

This is an image that, using the combined capabilities of NASA’s Hubble and Spitzer space telescopes, shows what is being described as the faintest object, and one of very oldest, ever seen in the early universe.  It is a small, low mass, low luminosity and low size protogalaxy as it existed some 13.4 billion years ago, about 4oo million years after the big bang.

The team has nicknamed the object Tayna, which means “first-born” in Aymara, a language spoken in the Andes and Altiplano regions of South America.

Though Hubble and Spitzer have detected other galaxies that appear to be slightly further away, and thus older, Tayna represents a smaller, fainter class of newly forming galaxies that until now have largely evaded detection. These very dim bodies may offer new insight into the formation and evolution of the first galaxies — the “lighting of the universe” that occurred after several hundred million years of darkness following the big bang and its subsequent explosion of energy.

This is an illustration by Adolf Schaller from the Hubble Gallery (NASA). It is public domain. It shows colliding protogalaxies less than 1 billion years afer the big bang.
This is an illustration by Adolf Schaller from the Hubble Gallery and shows
colliding protogalaxies less than 1 billion years after the big bang. (NASA)

Detecting and trying to understand these earliest galaxies is somewhat like the drive of paleo-anthropologists to find older and older fossil examples of early man. Each older specimen provides insight into the evolutionary process that created us, just as each discovery of an older, or less developed, early galaxy helps tease out some of the hows and whys of the formation of the universe.

Leopoldo Infante, an astronomer at Pontifical Catholic University of Chile, is the lead author of last week’s Astrophysical Journal article on the faintest early galaxy.  He said there is good reason to conclude there were many more of these earliest protogalaxies than the larger ones at the time, and that they were key in the “reionization” of the universe — the process through which the universe’s early “dark ages” were gradually ended by the formation of more and more luminous stars and galaxies..

But the process of detecting these very early protogalaxies is only beginning, he said, and will pick up real speed only when the NASA’s James Webb Space Telescope (scheduled to be launched in 2018) is up and operating.  The Webb will be able to see considerably further back in time than the Hubble or Spitzer.

Estimates of how many galaxies might exist in the universe are in flux, with recent studies producing results ranging from 100 to 225 billion.  On average a galaxy will have some 100 billion stars, giving the universe a low-end estimate of 10,000,000,000,000,000,000,000 stars.

When it comes to planets, a consensus of sorts has formed around the conclusion that in the Milky Way, and perhaps elsewhere, there is on average at least one planet per star.  So assuming that the planetary dynamics of our galaxy are similar to those of others, that’s an awful lot of potential exoplanets.

PSR B1620-26 b is an extrasolar planet located approximately 12,400 light-years away from Earth in the constellation of Scorpius. It bears the unofficial nicknames "Methuselah" and "the Genesis planet" due to its extreme age
PSR B1620-26 b is an extrasolar planet located approximately 12,400 light-years away from Earth in the constellation of Scorpius. It bears the unofficial nicknames “Methuselah” and “the Genesis planet” due to its extreme age. (NASA and G. Bacon, STScI)

All this has significant implications for the field of exoplanet research.

“We know that basically, planets form at about the same time as their stars from all the leftover dust and gas kicked up,” said Joel Green, Project Scientist at Space Telescope Science Institute’s Office of Public Outreach (STScI.)  The Institute operates the science for the Hubble Space Telescope as an international observatory.

“The earliest planets may have been very different kinds of planets because there was not as much metallicity (heavier elements) in those stars.  But as soon as you have stars, you have planets.”

He said that in theory, that means that when the very earliest stars formed — during a time when the universe was essentially dark — planets were formed too. “They don’t need a universe of light to form; they need one star.”

The most ancient exoplanet detected so far (PSR B1620-26 b) has had a rather unusual history, first born 12.7 billion years ago outside of a “globular cluster”  of stars (a comparatively older, compact group of up to a million old stars, held together by mutual gravitation), it then migrated closer to the cluster and into a rough astrophysical neighborhood. As viewed today, it orbits a pair of burned-out stars in the crowded core of a globular star cluster. It was first identified as a possible planet in 1992 — before the detection of 51 Pegasi b — but it took more than a decade to confirm that it is.

The oldest known exoplanet solar system is Kepler -444, formed 11.2 billion years ago in the Milky Way, itself 13.2 billion years old. Located in the constellation Lyra  116 light-years away, it hosts five rocky planets, all orbiting close to their sun.

Kepler-444 hosts five Earth-sized planets in very compact orbits. The planets were detected from the dimming that occurs when they transit the disc of their parent star, as shown in this artist's conception. Credit: Tiago Campante/Peter DevineKepler-444 is a metal-poor Sun-like star located in the constellation Lyra, 116.4 light-years away. Also known as HIP 94931, KIC 6278762, KOI-3158, and LHS 3450, this pale yellow-orange star is very bright and can be easily seen with binoculars. It was formed 11.2 billion years ago, when the Universe was less than 20 percent its current age. It is approximately 25 percent smaller than the Sun and substantially cooler.
Kepler-444 hosts five Earth-sized planets in very compact orbits. A metal poor sun (composed largely of hydrogen and helium), it is very bright and easily seen with binoculars. (Tiago Campante/Peter Devine)

The discovery of a solar system with rocky planets of this age (more than twice the age of our solar system’s rocky planet quartet), opens the door to the prospect of an early universe with many more rocky planets than once thought.  That means there could be vast numbers of very ancient Earth-like planets out there.

Returning to the faintest protogalaxy, it is described as being comparable in size to the Large Magellanic Cloud (LMC), a very small satellite galaxy of our Milky Way seen in the southern hemisphere. Tayna is rapidly making stars at a rate ten times faster than the LMC, and is likely the growing core of what will evolve into a full-sized galaxy.

This faintest ancient galactic find is part of a discovery of 22 young galaxies at ancient times located nearly at the observable horizon of the universe, research that substantially increases in the number of known very distant galaxies.

“The big unanswered question is how and when did the stars and galaxies turn on to end those Dark Ages,” said Green.  “There was a point when they started popping like popcorn.  With Hubble we can go back only so far and can’t see anymore, but the James Webb can go significantly further and see back to the Dark Ages.”

Massive cosmic objects, from single stars to galaxy clusters, bend and focus the light that flows around them with their gravity, acting like giant magnifying glasses. This effect is called gravitational lensing or, when it is detected on tiny patches on the sky, microlensing. Credit: ESA/ATG medialab Read more at: http://phys.org/news/2015-07-astronomers-cosmic-gravity-black-hole-scope.html#jCp
Massive cosmic objects, from single stars to galaxy clusters, bend and focus the light that flows around them with their gravity, acting like giant magnifying glasses. This effect is called gravitational lensing or, when detected on distant plants and faint galaxies, microlensing. (ESA/ATG medialab)

Ironically, Infante and his team were able to find the faintest distant galaxy so far without having it be the hardest to see.  That’s because they were able to use a technique of observing first proposed by Albert Einstein.  As described on the HubbleSite:

The small and faint galaxy was only seen thanks to a natural “magnifying glass” in space. As part of its Frontier Fields program, Hubble observed a massive cluster of galaxies, MACS J0416.1-2403, located roughly 4 billion light-years away and weighing as much as a million billion suns. This giant cluster acts as a powerful natural lens by bending and magnifying the light of far-more-distant objects behind it. Like a zoom lens on a camera, the cluster’s gravity boosts the light of the distant protogalaxy to make it look 20 times brighter than normal. The phenomenon is called gravitational lensing and was proposed by Einstein as part of his General Theory of Relativity.

While gravitational lensing uses a galaxy cluster as its magnifying glass, “microlensing” takes advantage of the same physics but uses a single star in our galaxy as the lens.  That technique is the only known method capable of discovering planets at truly great distances from the Earth. Radial velocity searches look for planets in our immediate galactic neighborhood, up to 100 light years from Earth, transit photometry can potentially detect planets at a distance of hundreds of light-years, but only microlensing can find planets orbiting stars near the center of the galaxy, thousands of light-years away.

And in the spirit of the wonder that microlensing tends to engender, let me leave you with another of those defining astronomical images that are impossible to ignore or forget.

This is the third version of the Hubble Ultra Deep Field, first assembled from 2003-2004 images, upgraded to the Hubble eXtreme Deep Field (XDF) image in 2012 and then enhanced further in 2014 and returned to the original Hubble Ultra Deep Field name.  Both the XDF and the 2014 version capture a patch of sky at the center of the original Hubble Ultra Deep Field.  That initial effort, which looked back in time approximately 13 billion years, picked up many unintentionally microlensed galaxies.

The newer images feature about 5,500 galaxies even within its smaller field of view. The faintest galaxies are one ten-billionth the brightness of what the human eye can see; just imagine that ratio for a single star or a planet.

So while there undoubtedly are an untold numbers of planets in the field, they will remain hidden for a very long time to come.

Hubble Ultra Deep from 2014. using full range of ultraviolet to near infrared, includes some of the most distant galaxies imaged by an optical telescope.
Hubble Ultra Deep Field from 2014. using full range of ultraviolet to near infrared, includes some of the most distant galaxies imaged by an optical telescope.  It is the third iteration of the Hubble Ultra Deep Field image, and combines more than 10 years of Hubble photographs taken of a patch of sky at the center of the original creation. (NASA)
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Retro Exo and Its Originators

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David Delgado, visual Strategist for NASA's Jet Propulsion Lab, co-designed the Orbital Pavillion sculpture for the World Science Festival in New York. (Ramsay de Give, The Wall Street Journal)
David Delgado, visual Strategist for NASA’s Jet Propulsion Lab, co-designed the Orbital Pavilion sculpture for the World Science Festival in New York. (Ramsay de Give, The Wall Street Journal)

Exoplanets are mysterious, they’re complicated, they’re important, they’re awe-inspiring.   And, to a team of artists at the Jet Propulsion Lab, they’re also totally fun.

They’re a topic for endless artistic creation because they’re that remarkable combination of brand new and, surprisingly, comfortably familiar.  Exoplanets may be weird and wild but they’re also potentially home to life and, well, people.  And what better way to describe and talk about exoplanets than in a context we all understand — as a travel destination where one of us just might some day spend some time.

Thus was born the series of exoplanet posters — created by artists of JPL’s imaginary Exoplanet Travel Bureau — that have caught the imagination of millions.  When the JPL team put highest quality copies of their posters onto their Planet Quest website in summer, the traffic was so great that the site crashed.

Where the sun shines red. (NASA/JPL)
Where the sun shines red.
        (NASA/JPL-Caltech)

We know that JPL is extraordinary when it comes to designing, building and then operating satellites and rovers, but extraordinary in art, too?

“We had this idea — we wanted to say something real about these planets, something based on firm scientific discoveries, but we also wanted it to be approachable and appealing,” said David Delgado, one of the three members of the JPL art team called “The Studio” which designed and produced the now iconic posters. He has a background in teaching (at JPL), in graphic communications and, initially, in advertising.

“Each poster would have one planet, and we would illustrate one strange or wonderful aspect of it.  It kind of caught on.”

While the idea of creating some exo-posters had been bouncing around for some time in the minds of three of the members of the JPL art team — Delgado, Joby Harris and Daniel Goods — it was a specific event and specific need that brought them to life.

Last year, MIT exoplanet pioneer Sara Seager was coming to JPL, and the exoplanet office wanted something special to greet her.  So it was a perfect moment to finally execute the exo-poster plan.  Three posters were created, one showing a super-Earth with low gravity, one a planet orbiting a pair of binary stars, and one where the nature of the sun’s radiation might produce vegetation of a different color than on Earth (if any vegetation existed, that is.)

A Tatoonie planet with two suns. (NASA/JPL)
A Tatoonie planet with two suns. (NASA/JPL-Caltech)

“They were supposed to be seen in hallway, just to kind of decorate the area for a welcome,” said Harris, the primary illustrator.  “It was really dark, so we had to figure out lighter colors to use and maybe a different kind of style.”

“Little did we know how it would take off.  People were stopping to look at the posters and figure them out, interns were taking pictures, summer students were flocking in,” he said.  “Pretty soon people were asking for copies and our office said, sure, let’s make copies.”

So those copies were released early this year and, because they are NASA products, they were all free.  News of the posters was soon all over Twitter and Reddit and JPL’s Planet Quest site (http://planetquest.jpl.nasa.gov/exoplanet_travel_bureau) came crashing down.

For first recipient Seager, her hallway introduction to the posters was a delightful “wow” moment:  “In exoplanets, so many things that happen surprise us by exceeding anything we could have imagined. Usually that sentiment is for new exponent discoveries, but in this case its for the how iconic the posters have become, and the public reaction to them.”  She has copies hanging in her home, in her office and uses them in her public talks.

None of the particular planets selected is considered habitable by the experts, but all had a human visitor included nonetheless.  And that’s how the seemingly visceral connection with viewers was made. Looking back, Delgado sees the inclusion of people as essential.

“There were some objections for sure to having people in the posters.  It seemed to be communicating that NASA was going to these places with astronauts, and clearly it is not,” Delgado said.  “But people want to place themselves on these planets, to be a viewer who experiences what it might be like.  As a way to get folks excited about exoplanets and learn, seems fine to me.”

Clearly, the look, the artistry of the posters was a driving force, too  Many illustrations of celestial bodies come with a kind of classic sci-fi imagination that emphasizes drama, collisions, sharp lined realism and bright colors.  The Travel Bureau posters are a polar opposite — retro and at times Art Deco. Some have pointed out that they look a tad like Amtrak’s travel posters or the work of a few artists experimenting in science fiction, but there’s no doubting that their work was novel.

Most fully Art Deco poster of a planet with no sun, created for a science gathering. (NASA/JPL)
Most fully Art Deco poster of a planet with no sun, created for a science gathering. (NASA/JPL-Caltech)

It was illustrator Harris who brought that sensibility to the project.  He has a background in special effects, graphics and film– where he was exposed to the art deco look.  He also works in television; one of his early projects was to design some of the props for what became the cult science fiction series “Firefly.”

The poster’s retro look came from a desire to meld nostalgia and the past with the cutting edge future — a return to travel posters of the 20s and 30s, but with rather different destinations.

“We were aiming for a retro-futuristic look, something that brings science fiction into the everyday present,” Delgado said. “It’s like we’re living in the future, or science fiction is coming to life.”

The look has indeed spawned much competition from private artists, who have created planetary and exoplanetary posters in a similar vein.  Delgado thinks that many are just fine, but a little limited.  “Everyone loves the look.  But some capture the fun without the truth of the science.”

Poster for the 20th anniversary celebration in Washington of the discovery of earliest exoplanets. (NASA/JPL)
Poster for the 20th anniversary celebration in Washington of the discovery of earliest exoplanets. (NASA/JPL-Caltech)

“Visual Strategist” Daniel Goods was the artistic director for the project, and he was the one who came up with the idea of adding a line of text highlighting the science.  Goods, like the others, has also created substantial art and sculpture installations around the JPL campus, some of which tour the nation and the world and have won awards. The posters, for instance, are now on display at a major art exhibition in Stockholm.

Goods is a native of Alaska with little science background, who grew up in Oregon and Seattle somehow now shines in L.A.  He and the others say they thrive on asking questions of the scientists and integrating their knowledge into “The Studio’s” work.

The posters took particular outreach and study to get the right scientific message:

“Where Your Shadow Always has Company” for a planet orbiting a set of binary stars.

“Where the Nightlife Never Ends” for an orphan planet no longer orbiting a sun.

A super-Earth and its gravity (NASA/JPL)
A super-Earth and its gravity (NASA/JPL-Caltech)

“Experience the Gravity of HD 40307d for a super-Earth where the force of gravity would be much stronger than on Earth.

“Where the Grass is Always Redder on the Other Side” for a planet orbiting a sun cooler than ours and emitting radiation in redder wavelengths.

Given the huge success of the posters, the logical question to ask is whether more are coming, and when.

I certainly asked the question but those who know said they couldn’t answer.

Nonetheless, I think there’s reason to be optimistic that more clever and compelling planetary and exoplanetary art will be coming out of the JPL “Studio” in the months and years ahead.  And some will no doubt be retro.

So stay tuned.

Joby Harris (left) and Dan Goods in "The Studio" at JPL. (NASA/JPL)
Joby Harris (left) and Dan Goods in “The Studio” at JPL. (NASA/JPL-Caltech)
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