7 Earth-Sized Worlds Discovered Orbiting Nearby Star

Artist's concept of the surface of TRAPPIST1-f.

Artist’s concept of the surface of TRAPPIST1-f. – Credit: NASA/JPL-Caltech

NASA held a press conference today, announcing an exciting new discovery: A record-breaking seven Earth-sized planets have been discovered orbiting a star located about 40 light years from Earth. Three of these planets are firmly located within what’s called the habitable zone–the area around a star that is likely to have rocky planets with liquid water.

The star is named TRAPPIST-1 (also known as 2MASS J23062928-0502285). It’s an ‘ultra-cool dwarf’ star, with approximately 8% of the mass and 11% of the radius of our Sun. Size-wise, this is approximately the difference between a basketball and a golfball.

The seven plants surrounding TRAPPIST-1 orbit much closer to their star than Earth does to the Sun. As well, these exoplanets are much closer to each other than the planets in our own system. You could stand on one of these planets and see the next closest one with a similar type of view that we have with the Moon here on Earth, and you could clearly make out the disc-shape of many of the other planets rather than mere points of light.

The discoveries were made using data from the Spitzer Space Telescope, which was launched in 2003. Although Spitzer wasn’t specifically designed to observe exoplanets, the suite of instruments it carries allows it to discover exoplanets in the same manner that the Kepler spacecraft uses. These observatories can discover exoplanets by precisely measuring dips in the light emitted from a star that coincides with a planet orbiting in-between that star and our vantage point and blocking a portion of the light that we can measure. Continued observations can determine orbital periods, distance from the star, and the number of exoplanets in a system. This data can be used to plot habitable zones.

During the press conference, the team stated that they had preliminary mass measurements for six of the planets, and they believe that one is likely to have a water-rich composition.

Artist's concept shows what each of the TRAPPIST-1 planets may look like, based on available data about their sizes, masses and orbital distances.

Artist’s concept shows what each of the TRAPPIST-1 planets may look like, based on available data about their sizes, masses and orbital distances. – Credit: NASA/JPL-Caltech

There currently isn’t a system for naming exoplanets in the way that bodies like asteroids are named, so they’re simply provided with alphabetic designations appended to their host stars’ name, with the designation ‘b’ being the closest to the star.

These planets orbit so close to their star that they’re likely tidally-locked in the same manner that the Moon is to the Earth. These planets would have permanent day and night sides.

One of the planets, Trappist-1c, is very similar in size to Earth and receives about the same amount of light as Earth receives from the Sun. It could very well have temperatures similar to those we have on Earth. Trappist-1f has a 9-day orbit and receives about as much light as Mars does. Trappist-1g is the largest planet in the system with an estimated radius 13% larger than Earth.

All of the planets are within a few times the distance between the Earth and the Moon of each other, and being so close to their star their orbits (their years) are about 1.5 Earth days for the closest planet and 20 days for the furthest.

Concept art for TRAPPIST-1 and its seven Earth-sized exoplanets.

Concept art for TRAPPIST-1 and its seven Earth-sized exoplanets. – Credit: NASA/JPL-Caltech

The next step, which is already ongoing, is to study their atmospheres and to look for water. This can be accomplished using a technique called transmission spectroscopy. We have observatories that can do this now, such as the Hubble Space Telescope, and the future James Webb Space Telescope (JWST) will be able to push these capabilities even further. JWST will be able to look for greenhouse gas content and determine the surface temperatures of these planets, as well as detect gases that are produced by life. It’s expected that the first cycle of observations of the JWST will include the TRAPPIST-1 system.

Thomas Zurbuchen, associate administrator of the agency’s Science Mission Directorate in Washington, referred to our moment in time as “the gold rush phase of exoplanet discovery.”  It was just in 1995 that the first exoplanet was discovered, he explained, and that thousands have been discovered since.

Following the announcement, the panel held a Q&A session. During the course of their answers, they explained that there was no indication of these planets having moons, but that if water was present there would be tidal activity resulting from the other planets. They said they expect substantial progress in determining the atmospheric composition of these exoplanets within the next 5 years, utilizing the Hubble Space Telescope and the James Webb Space Telescope after it begins operations in 2018. JWST’s transmission spectroscopy will cover the range needed to determine the potential for life.

One member asked if any attempts have been made to listen to the system with SETI-style instruments, to which there was a reply that SETI itself had listened to the system but hadn’t picked-up any signals.

One of the most interesting answers came from Zurbuchen, when he was asked when we could expect to construct a craft that could journey to this system. Rather than give an estimate in the number of years in the future we could expect such capabilities, he answered with the estimated “number of miracles” that are required before we get there. He explained that the JWST required 10 miracles to become possible. He likened the construction of a craft that could explore TRAPPIST-1 as requiring “100 miracles”, but that we shouldn’t be dissuaded, that to get there you have to “start inventing your way forward.” Some of the “miracles” require advancements in propulsion systems and radiation-protection, and that the good news was that substantial work is already being accomplished towards about 5-10 of these miracles. He said it’s about “leaning forward” and “not backing up”.

Discoveries like these are constant reminders of just how big and amazing our Universe is. We’re reminded that the night sky isn’t just full of points of light, but worlds, perhaps some of which might be very similar to our own.

A poster advertising a hypothetical planet-hopping trip in the Trappist-1 system

A poster advertising a hypothetical planet-hopping trip in the Trappist-1 system – Credit: NASA-JPL/Caltech

In Memoriam: Captain Donald Edward Williams

Captain Donald Edward Williams


Captain Donald Edward Williams passed away on Tuesday, February 23, 2016. He was 74.

Early Life, Education, and Military Service

Donald Edward Williams was born on February 13, 1942, in Lafayette, Indiana. He grew up working on his father’s farm, spending his time after school running tractors, tending to animals, and completing general repairs. While working, he always took note of the jets flying overhead and thought to himself that being up there looked like a lot more fun that what he was doing down in the dirt. He graduated Otterbein High School, Otterbein, Indiana, in 1960 before earning a bachelor of science degree in Mechanical Engineering from Purdue University. At Purdue, he received his commission through the Naval Reserve Officers Training Corps (NROTC). He completed flight training in Florida, Mississippi, and Texas, earning his pilot wings in 1966.

Williams completed a total of  four deployments to Vietnam, aboard USS Enterprise, as a member of Attack Squadron 113 and Attack Squadron 97. During his deployments, he flew a total of 330 combat missions. After Vietnam, Williams enrolled at the Armed Services Staff College, graduating from the U.S. Naval Test Pilot School in 1974.

Williams was selected as a member of the NASA class of 1978, also known as Astronaut Group 8 or the Thirty Five New Guys (which, I must point out, included gals, too). This was the first new group of astronauts since 1969. He served in various capacities at NASA until being pegged to serve on two separate Space Shuttle missions:


STS-51-D Mission Patch

STS-51-D Mission Patch

He served as pilot on Space Shuttle mission STS-51-D, which was completed on shuttle Discovery in 1985. That mission included completing a number of experiments (including some utilizing simple toys, with the results being shared with school students), and launching a couple of satellites. One of the satellites malfunctioned upon deployment. As a result, NASA authorized its first unscheduled 3-hour EVA (extravehicular activity).

According to the book, Discovery: Champion of the Space Shuttle Fleet:

The mission became an ingenious effort to avert failure by improvising a difficult rescue without prior training. As engineers and astronauts on the ground devised a solution, they sent instructions to the crew to use on-board materials to make something like a flyswatter and a lacrosse stick.


Additionally, that Discovery mission included the first elected government official to fly in space. Utah Senator Edwin Garn joined the crew as Payload Specialist 2, acting as a congressional observer to the program. (Talk about perks of the job!)


STS-34 Mission Patch

STS-34 Mission Patch

Williams served as Commander of his second and final spaceflight in 1989, on mission STS-34 aboard shuttle Atlantis. A notable accomplishment of that mission was the deployment of the Galileo spacecraft, which became the first spacecraft to orbit and penetrate the atmosphere of an outer planet.

In a 2002 interview with Rebecca Wright, as part of a NASA Johnson Space Center Oral History Project, Williams reflected on the STS-34 mission:

I really enjoyed that mission probably even more so than the first because it was my goal to command a mission, first of all, and I got to do that. But secondly, because we knew that Galileo was going to be a lasting program as opposed to the first flight, [where] we deployed the two satellites, [but] it turned out to be a unique flight, too, because of the spacewalk. The Galileo mission we knew, if it was successful, the spacecraft was going to end up in orbit around Jupiter several years later and then there [were] going to be several years of data and images sent back. It was going to be a living, ongoing program, and we got to be a part of it. That was a really unique experience.


Williams retired from the U.S. Navy, having earned the rank of Captain, and left NASA. He completed numerous projects as a Division Manager with Science Applications International Corporation before his retirement in 2006.

During Williams’s career, he earned the following special awards and commendations: The Legion of Merit, Distinguished Flying Cross, Defense Superior Service Medal, 2 Navy Commendation Medals with Combat V, 2 Navy Unit Commendations, a Meritorious Unit Commendation, the National Defense Medal, an Armed Forces Expeditionary Medal, the NASA Outstanding Leadership Medal, the NASA Space Flight Medal, the NASA Exceptional Service Medal, the Vietnam Service Medal (with 4 stars), a Vietnamese Gallantry Cross (with gold star), and the Vietnam Campaign Medal.

From his roots as a rural farm-boy with his eyes in the sky, to serving his country valiantly in four deployments during the Vietnam war, and finally having the honor to fly two space shuttle missions as a Pilot and a Commander, Donald E. Williams was a true American hero. He was among the best of the best and should serve as an inspiration for centuries to come. We thank you for your service and honor your legacy.

Godspeed, Mr. Williams.

NASA Astronaut Don Williams aboard Space Shuttle Atlantis

NASA Astronaut Don Williams aboard Space Shuttle Atlantis – Source: NASA


Explorer 1: America's First Space Satellite

Explorer 1

Explorer 1 – Source: NASA

You probably know that Russian Sputnik satellite was the first human-made satellite to be placed into orbit. If not, I’m guessing you’ve at least heard of it. While the Russians beat the United States in that first declaration of space dominancy, America wasn’t far behind. Today we learn the story of the United States’s first orbital satellite: Explorer 1 1.

Towards the end of 1957, news of the Russian’s space accomplishments was rocketing around the world. Their successful Sputnik spacecrafts had recorded new entries in world history: Sputnik 1 was the first human-made object put into Earth orbit; and Sputnik 2 carried the first living creature larger than a microbe, a poor dog sacrificed in the name of science, named Laika.

The United States’s credibility was in question. Could the US compare to the Russian’s space prowess?

News of Sputnik’s milestones kickstarted an otherwise stalled United States space satellite program. The United States Army Ballistic Missile Agency (ABMA), directed by Wernher von Braun, teamed up with the federally-funded research facility, JPL (Jet Propulsion Laboratory) under the direction of Dr. William H. Pickering. JPL designed the Explorer 1 craft, while the ABMA modified one of its Jupiter-C rockets (gaining the designation Juno 1) to carry Explorer 1 payload into orbit.

A few months prior, in December of 1957, the United States Navy had attempted to put the first US satellite in orbit. That rocket made it about four feet above the launchpad before failing catastrophically in a magnificent ball of fire. Its failure earned such laughable nicknames as: Flopnik, Stayputnik, Oopsnik, and my favorite, Kaputnik.

Rapid work began on the satellite and launch system, and in only 84 days they had completed the design, construction, and assembly of Explorer 1 and its complementary rocket.

Explorer 1 schematic

Explorer 1 schematic – Source: NASA

Explorer 1 consisted of two major components: the 37.25 inch scientific portion, containing science and communication instruments, mated to a 45.5 inch rocket booster. This package was placed atop the 70-foot-tall Juno 1: a four-stage, Redstone-family booster rocket.

Explorer 1 launched from Cape Canaveral, Florida, at 10:48pm local time on January 31, 1958.

Explorer 1 entered an eccentric orbit around Earth, with the closest point in its orbit at 358 kilometers (222 miles) and its furthest at 2,550 kilometers (1,580 miles). It completed an orbit every 114.8 minutes. Mercury batteries powered the craft’s high-power transmitter for 31 days, with the low-power transmitter operational for 105 days. Explorer 1’s final transmission was received on May 23, 1958. The silent Explorer 1 continued to orbit for more than 12 years, its orbit finally decaying to the point of re-entry and destruction in the atmosphere over the Pacific on March 31, 1970. By then, it had completed more than 58,000 orbits.

Explorer 1 effectively initiated the Cold War space race. But it did more than just prove that the United States could compete with the Russians in putting things in orbit. Explorer 1 conducted real science and made some important discoveries that would be important to understand as the world progressed into a space-faring society.

Explorer 1 contained two main scientific instruments: one for detecting cosmic rays, and another for studying micrometeorites.

The micrometeorite package consisted of a “wire grid (arrayed around the aft section of the rocket body) and an acoustic detector (placed in contact with the midsection)“. Over the course of the experiment, 145 micrometeorite hits were detected.

The cosmic ray detection equipment made even greater discoveries. This was accomplished by an “Anton 314 omnidirectional Geiger tube detector“, which measured the flux of charged particles hitting the detector. The experiment was overseen by Prof. James A. Van Allen.

A peculiarity was noted in this experiment: the expected radiation count was approximately 30 per second, but the detector would occasionally return a result of zero. It was determined that these zero count intervals coincided with altitudes greater than 2,000 kilometers (1,200 miles). Further research determined that at those altitudes, the detector was actually being over-saturated and overwhelmed by the radiation. This led to the discovery of an energetic belt of charged particles that surround magnetized planets , such as Earth. This belt was named after James Van Allen, and today are known as Van Allen radiation belts. Knowledge of this region would become essential to the survival of humans that would travel through them in later space programs. The discovery was designated as one of the greatest of the International Geophysical Year.

William Hayward Pickering, James Van Allen, and Wernher von Braun at a press conference announcing the orbital insertion of Explorer 1.

William Hayward Pickering, James Van Allen, and Wernher von Braun at a press conference announcing the successful orbit insertion of Explorer 1 – Source: NASA

At around 1:00 am on February 1, 1958, just hours after Explorer 1’s successful orbit insertion was verified, William Hayward Pickering, James Van Allen, and Wernher von Braun were ushered to the National Academy of Sciences building in Washington, D.C.  to conduct a press conference that would make headlines around the globe.

That press conference produced one of the most iconic images of the Space Age. In the image, Pickering, Van Allen, and von Braun stand triumphantly, holding a model of Explorer 1 high above their heads.

A Moment in Time: Explorer 1 – Each of these three men thus represented a component of Explorer 1’s success: the rocket, the satellite and the science payload. Each represented an institutional underpinning crucial to the fledgling American space program: the Army, the Jet Propulsion Laboratory and scientific research as represented by the University of Iowa. Each had converged from his own path to the singular moment depicted in the triumphal image.


The success of Explorer 1 can’t be overstated. It proved the efficiency that could be achieved through collaboration between civilian and military agencies, it was one of the major sparks that ignited the Cold War space race, and it confirmed the United States as a powerful contender to the Russians.

  1. At the time of launch, also designated as Alpha 1958

Exciting Kepler News – Part 2: New Circumbinary Planets

 There were two exciting Kepler (the NASA mission tasked with discovering planets outside of our solar system) news released yesterday. I’m covering them in two separate posts. This is Part 2; read Part 1.

The second exciting Kepler news release is one of the most interesting yet; in fact, this discovery confirmed the existence of an entirely new class of planetary system! Today, astronomers announced the discovery of two new “circumbinary” planet systems; these follow the first circumbinary planet system announced in September of last year, the planet Kepler-16b.

So what does circumbinary mean anyway, and why is it so interesting? Let me answer the first question, which should preclude the need to answer the second.

Scene from Star Wars Episode IV: A New Hope, showing binary stars from Tatooine.
Classic scene from Star Wars Episode IV: A New Hope, showing a dual sunset from the circumbinary planet, Tatooine.

A circumbinary planet is one that orbits not one, but two stars. When Kepler-16b was confirmed last Fall, it wasn’t clear whether we should expect many more circumbinary planets or if that system was just a fluke. With the discovery of these two new systems, it is becoming apparent that circumbinary planets are abundant.

What makes this interesting is that binary-star systems are abundant in our galaxy. From the report published in Nature:

The observed rate of circumbinary planets in our sample implies that more than ~1% of close binary stars have giant planets in nearly coplanar orbits, yielding a Galactic population of at least several million.

At least several million!

As for the planets themselves, they are both gas giants about the size of Saturn.  Kepler-34b orbits its binary-pair of Sun-like stars every 289 days, while the stars themselves orbit and eclipse each other every 28 days. Kepler-35b orbits its smaller pair of stars every 131 days, with the stars orbiting and eclipsing one another every 21 days.  The Kepler-34 and Kepler-35 systems lie in the constellation Cygnus, 4,900 and 5,400 light-years from Earth, respectively.

For more information, check out these links:

NASA Kepler News Release

The paper, published in Nature

The news release for Kepler-16b, the first circumbinary planet discovered

Right Place Right Time: Good Luck Discovery

Talk about being at the right place at the right time. A few lucky passengers on a commercial jet flight leaving Orlando got a unique view of the shuttle Discovery’s final launch. Lucky for us, one of those passengers recorded a video.

What a fantastic perspective to view Discovery’s final voyage from.

10-Year-Old Girl Discovers Supernova

Supernova Remnant N49

Supernova Remnant N49 in the Large Magellanic Cloud - Courtesy NASA/JPL-Caltech

Across the world, many children spent their Christmas vacation sleeping in, making snowmen (and snowwomen), and playing video games.

10-year-old Kathryn Aurora Gray, instead discovered a supernova!

Kathryn was studying images sent to her father at an amateur observatory. To find supernovas, astronomers comb through dozens of past images of star fields and compare them to newer images; specialized software helps indicate potential supernova candidates.

The Royal Astronomical Society of Canada confirmed the find (.pdf) on January 3.

Her discovery made her the youngest to accomplish such a feat. Her father set the same record in 1995, when he was 22.

I can only imagine how cool she’s going to be in science class from now on. My kids’ teachers sometimes have to face my kids correcting them when they point out a planet incorrectly (“No, that’s not Jupiter, that’s Venus… My dad pointed it out and we were talking about it this morning!”), but they have yet to pipe up in class and say “Of course I know what a supernova is, I already discovered one!”

It’s quite exciting to see a young student so interested in science, and at such a young age, already carving a name out for herself in the astronomical community.

Congratulations Kathryn! Keep up the good work!