Pioneer 10 and 11 launched in 1972 and 1973, respectively, and were Earthkind’s first explorers of the outer planets and emissaries to deep space. Pioneer 10 became the first spacecraft to pass through the asteroid belt and observe Jupiter up-close, providing us with details of the gas giant’s interior, atmosphere, magnetic fields, and some of the most breath-taking images of Jupiter we had ever seen. Pioneer 11 wasn’t far behind, and after making its own observations of Jupiter, it went on to Saturn to open our eyes to the mighty ringed planet in the same way Pioneer 10 had done for Jupiter. (But this isn’t a story about the accomplishments of the Pioneer program; I’ll save that for another day.)
In addition to all of the data and images sent back, however, those two Pioneers also sent back a mystery. As early as 1980, it was noticed that the spacecrafts were experiencing an acceleration force toward the sun of .000000000874 m/s2 (meters per second, per second). To be clear, this does not mean the Pioneers are heading back towards the Sun. Pioneer 10 and 11 are cruising away from the Sun at a speed of around 132,000 kilometers per hour (82,000 miles per hour) and 175,000 kilometers (110,000 miles per hour), respectively, and this force is 10 billion times smaller than the acceleration we feel from the Earth’s gravitational pull. Nonetheless, the force is real and our instruments and techniques are precise enough to notice.
Many plausible causes were considered to explain the anomaly, including:
perturbations from the gravitational attraction of planets and smaller bodies in the solar system; radiation pressure, the tiny transfer of momentum when photons impact the spacecraft; general relativity; interactions between the solar wind and the spacecraft; possible corruption to the radio Doppler data; wobbles and other changes in Earth’s rotation; outgassing or thermal radiation from the spacecraft; and the possible influence of non-ordinary or dark matter.
In 1994, a thorough, long-term, collaborative study was undertaken to try and solve the anomaly. Initial results from that study were released in 1998, with a detailed analysis following in 2002. All known systematics were tested and calculated, yet that 8.74±1.33×10−10 m/s2 deceleration force remained. The origin of the anomaly was still unaccounted for, though the leading theory was that it was the result of anisotropic thermal radiation (don’t let the big words intimidate you, this just means heat was being radiated from the Pioneers in a certain direction). In 2004, another paper was published, proposing a deep space mission to solve the anomaly once-and-for-all.
But now, that expensive deep-space mission won’t be necessary, according to a paper just submitted by astrophysicist Slava Turyshev and his team of scientists and engineers, with thanks, in no small part, to The Planetary Society and its members.
With funds provided by The Planetary Society, Turyshev and his team were able to collect and compile great volumes of data from the two Pioneer missions. The data had to come from a variety of different sources and came in any number of formats, media, and condition. According to Bruce Betts, Director of Projects at The Planetary Society:
“This was not an easy (or quick) task. These missions lasted for more than 30 years. Imagine all the people, computing formats, and hardcopy and electronic storage devices involved over that period, and you’ll start to get an idea of the problem.”
Think of what you would have to go through if I handed you a 5.25″ floppy disk that contained… well, it couldn’t contain much compared to the amount of data we exchange today, but whatever it was, it was something you needed. Imagine trying to find the hardware to read the disk, and then the intermediary hardware and software that would be required to get the data from the disk onto one of today’s modern machines so you could even utilize it. If you consider how much technology has changed between now and floppy disks, you can only begin to imagine how much it has changed since the 1970s and how cumbersome compiling all of this data, let alone securing it, must have been. I digress.
Once Turyshev and his team were able to assemble the more-complete data picture, they were able to isolate the source of acceleration: that anisotropic thermal radiation. Again, Bruce Betts:
Why was the thermal emission from the spacecraft anisotropic and slowing the spacecraft down? First of all, because the Pioneer spacecraft were spin-stabilized and almost always pointed their big dishes towards Earth. Second of all, because two sources of thermal radiation (heat) were then on the leading side of the spacecraft. The nuclear power sources, more formally Radioisotope Thermoelectric Generators (RTG), emitted heat towards the back side of the dishes. When the dishes reflected or re-radiated this heat, it went in the direction of travel of the spacecraft. Also, the warm electronics box for the spacecraft was on the leading side of the spacecraft, causing more heat to spill that direction. Photon pressure, the same type of thing used in solar sailing, then preferentially pushed against the direction of travel, causing a tiny, but measurable, deceleration of the spacecraft – the Pioneer Anomaly.
At the end of the day, there are a few take-home lessons to be learned. First, Occam’s Razor proved itself once again (some of the suggestions to account for the Pioneer Anomaly were the need to invoke a new type of exotic physics). The second is that you can’t just apply Occam’s Razor and say that anisotropic thermal radiation is the simplest theory and therefore correct, you have to painstakingly collect all of the data needed to prove it — and more importantly, you have to have the experts that are willing to put forth the
years decades of research to solve the mystery. Finally, you take in the account that this was made possible with the help of citizen scientists and those of us that contribute to furthering our understanding of the Universe, through means such as The Planetary Society.
This new paper will undoubtedly generate more discussion about the Pioneer Anomaly and others will work to verify or disprove its results, but at this point it seems pretty safe to say that one of space physic’s mysteries is no more.
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They took rocket-grade kerosene and liquid oxygen, and turned it into 1.5 million pounds of thrust, 32 million horsepower, and made it possible to take the Apollo astronauts to the Moon. I’m talking about the Rocketdyne F-1 rocket engines used in the first stage of Saturn V — the only vehicle to take humans outside of low-Earth orbit.
Following launch, five F-1 engines would burn for about 2-and-one-half minutes, boosting the Saturn V and its payload to an altitude of nearly forty miles, and 55 miles downrange from Cape Kennedy. At that point, the first stage (S-1C) containing the F1 engines would separate from the rest of the Saturn V and fall back to Earth, crashing into the Atlantic Ocean where they would rest forever.
(Image Credit: NASA)
At least, forever was how long we thought they would sit there….
Amazon.com founder, Jeff Bezos, recently announced that a “team of undersea pros” that he funded had found the most famous F-1 engines of all; the ones from Apollo 11 that launched humanity to the Moon, where the first humans would walk on another world. But finding them is just the start, Bezos Expeditions is planning on actually recovering one or more of the F-1s.
“We don’t know yet what condition these engines might be in – they hit the ocean at high velocity and have been in salt water for more than 40 years. On the other hand, they’re made of tough stuff, so we’ll see”, Bezos said in the announcement. He also pointed out that regardless of how long the engines have spent 14,000 feet below the surface of the Atlantic, they are still the sole property of NASA. He also stated that he had requested that NASA make available for display at the Museum of Flight in Seattle, Washington, the second F-1 his group manages to salvage (the first presumably would go to the Smithsonian).
NASA followed the announcement with a press release of their own, in which NASA Administrator Charles Bolden expressed his support for the project, and acknowledged the request to house a second (or the first, if the Smithsonian declines it) F-1 at Bezos’ requested facility.
“NASA does retain ownership of any artifacts recovered and would likely offer one of the Saturn V F-1 engines to the Smithsonian Institution’s National Air and Space Museum in Washington under long-standing arrangements with the institution as the holder of the national collection of aerospace artifacts.
“If the Smithsonian declines or if a second engine is recovered, we will work to ensure an engine or other artifacts are available for display at the Museum of Flight in Seattle, as Jeff requested in his correspondence with my office.”
As of yet, there hasn’t been an announced timeline, cost, or specific details released about the project; however, I personally suspect Bezos will have no problem pulling together the resources needed to tackle the feat.
Bezos ended the announcement with a quote that echoes my own heart when it comes to NASA’s ability to inspire:
NASA is one of the few institutions I know that can inspire five-year-olds. It sure inspired me, and with this endeavor, maybe we can inspire a few more youth to invent and explore.
Good luck, Bezos Industries. Thanks for taking the public treasure that NASA is and multiplying its inspiration for generations to come.
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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.
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:
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There were two exciting Kepler (the NASA mission tasked with discovering planets outside of our solar system) news releases today. I’ll cover them in two separate posts. This is Part 1; stay tuned for Part 2.
Announced today was the discovery of the three smallest exoplanets (planets orbiting a star other than the Sun) ever discovered. These planets are orbiting a red dwarf star, currently named KOI-961 (KOI = Kepler Object of Interest). These planets are all smaller than our home planet, having a radius of .78, .73, and .57 that of Earth’s. (The smallest is about the size of Mars.) Though the planets are thought to be rocky, they orbit KOI-961 very closely, making them too hot to have any likelihood of being habitable.
The planets, currently named KOI-961.01, KOI-961.02, and KOI-961.03, circle their host star at a fair clip, completing an orbit in less than two Earth-days. The star, KOI-961, has much less mass than our Sun. Its diameter is 1/6 the size of the Sun (which is only about 70% larger than Jupiter).
The discovery announced today came from a team of scientists, led by astronomers from the California Institute of Technology (Caltech). They made their discovery by analyzing publicly-released data from the Kepler mission. Studying KOI-961, they were able to greatly refine the preliminary estimated size of the red dwarf, and subsequently verify the presence of the three small exoplanets.
(Click to enlarge / Image Credit: NASA/JPL-Caltech)
If you’re interested in further details about how Caltech made the discovery, I highly recommend you read their press release.
So let’s take a step back and ponder about what this latest discovery means. Coupled with the many frequent previous Kepler discoveries, we’re starting to create a big picture in which planets are ubiquitous throughout the Universe. Red dwarfs are the most common type of star in at least our own galaxy, and if one red dwarf has a planetary system, it’s likely more do… maybe even most do. We’re discovering planets around different types of stars; those similar to the Sun and those considerably different. Planets of different sizes and compositions as well. Not just large gas giants with little hope for containing life, but smaller, rocky worlds. Other Earth-sized worlds. Other Earth-like orbits. Other… Earths.
The speed at which we’re making these otherworldly discoveries is astounding and encouraging. It wasn’t long ago, I sat wondering if there were other planets out there, beyond our solar system, and if they might be discovered in my life. Today, I’m overwhelmed trying to keep up with all of the new exoplanet discoveries!
This is an exciting era to live in.
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NASA just announced that the Kepler mission has discovered the first Earth-sized planets outside of our solar system.
The planets, Kepler-20e and Kepler-20f, while Earth-sized and thought to be rocky, are not believed to be habitable. They are much too close to their Type G star, Kepler-20, and too hot to retain liquid water. Kepler-20e has a radius about 13% smaller than the Earth, making it just slightly smaller than Venus, and whips around Kepler-20 in a mere 6.1 days. Kepler-20f has a radius 3% larger than that of the Earth, with its year being a still fast 19.6 days. The Kepler-20 system is approximately 1,000 light years from Earth.
Read the NASA release for even more details.
The Kepler mission is playing out like the fairy-tale, Goldilocks and the Three Bears. By that, I mean that we’re closing in on those planets that are “just right” for harboring life. We’ve discovered large planets inside the habitable zone that lacked a rocky surface (Kepler-22b) and gas giants not unlike Jupiter. Today, we’re finding Earth-sized planets with a rocky terrain. We’re getting ever so close to discovering those “Goldilocks” planets, with the size, composition, and being within the habitable zone, that allow them to be habitable. And with more than 2300 candidates out there still waiting to be verified by Kepler, and Kepler’s current rate of discovery, I believe the announcement of a goldilocks planet is just around the corner.Continue Reading »
Kepler keeps on Kepler-ing on.
Earlier this year, I mentioned that the Kepler mission team was about to make an announcement the following day about a new discovery. The following day, the Kepler team announced the confirmation of a 9th exoplanet. Then, just earlier this week, I posted about Kepler’s 28th confirmed discovery, Kepler-22b. Kepler-22b was exciting, as the data reveals that it exists within the habitable zone of its host star.
Well, Kepler is set to make another announcement tomorrow!:
NASA’s Kepler Announcing Newly Confirmed Planets
MOFFETT FIELD, Calif. — NASA will host a news teleconference at 1 p.m. EST, Tuesday, Dec. 20, announcing new discoveries by the Kepler mission.
Kepler is the first NASA mission capable of finding Earth-size planets in or near the “habitable zone,” the region in a planetary system where liquid water can exist on the surface of an orbiting planet. Although additional observations will be needed to reach that milestone, Kepler is detecting planets and possible candidates with a wide range of sizes and orbital distances to help scientists better understand our place in the galaxy.
We’ll check back in tomorrow to learn what new and exciting discovery Kepler has for us.
*UPDATE: The press conference starts in 1pm (EST); you can listen to it live at this link: http://www.nasa.gov/news/media/newsaudio/index.htmlContinue Reading »
At the beginning of this year, we were excited to help break the news of the 9th planet confirmed by the Kepler spacecraft. Not even an entire year later, Kepler is up to 28 confirmed planets and more than 2000 more candidates waiting to be studied and potentially verified!
Last week, the Kepler mission had a very exciting announcement: Kepler-22b became the first exoplanet to be located within the habitable zone.
So let’s take a look at this exoplanet. Kepler-22b has a radius around 2.4 times that of the Earth. It is located 587 light-years from Earth, orbiting a star not so much different than our own. Though Kepler-22b’s host star — Kepler-22 — is slightly smaller and cooler than the Sun, Kepler-22b orbits closer than the Earth does to the Sun, compensating for the difference. Kepler-22b’s mass and surface composition is still unknown.
(Diagram showing a comparison between our solar system’s habitable zone with Kepler-22′s. / Credit: NASA/Ames/JPL-Caltech)
So, we have a planet not too much larger than the Earth (though we don’t know its composition or mass), orbiting a star not too much smaller/cooler than our Sun, in the so-called habitable zone. What are the chances of life? First, we have to remember that while the Earth sits in our solar system’s habitable zone, so does Mars, Ceres, and sometimes Venus, and those are hardly bodies that appear to be very conducive for life (though, I think the book on Mars still has many pages to be read). But, then there’s the Earth, that Goldilocks planet within Sol’s habitable zone; life flourishing.
So. Not only is Kepler looking in the right places but it is finding what it is looking for, and proving quite able to find out just how rare planets like our own might be. At 587 light years from Earth we won’t be sending a probe to Kepler-22b to do reconnaissance anytime soon, but this discovery does fuel our imaginations, fill our minds with knowledge, and inspire us to carry on looking. At the very least, it proves just how capable the Kepler spacecraft is and just how amazing the mission truly is.Continue Reading »
This was a fascinating find, as the planet discovered — Kepler-10b — is only 1.4 times the size of Earth, and probably terrestrial (rocks and metal; not a gas giant) in nature. This discovery marks the smallest exoplanet yet discovered! Not bad, for something 560 light years away.
Remember, Kepler’s goal is to discover “Earth-like” planets, and then determine how many of them might be in a habitable zone. Is Kepler-10b habitable? It would be highly unlikely. The planet orbits its host star, Kepler 10 (see how they do that?), in an orbit that brings it much closer than Mercury is to the Sun; more than 20 times closer. This means Kepler-10b is hot… several thousand degrees hot! On top of that, it has more than 4-and-half times the mass of the Earth. Standing on Kepler-10b would give new meaning to the phrase, “hot and heavy”.
Another interesting bit of information, is that it’s expected to be tidally locked to Kepler 10. Just as the Moon only shows its one face to Earth, Kepler-10b only shows one face to its star. My imagination quickly conjures up an imagination of a planet habitable on one side, and a scorched realm of hellfire on the other — but the facts probably indicate the entire thing is closer to the latter; a big dense glob of molten material.
So, let’s quickly recap some of the highlights of Kepler’s 9th confirmed exoplanet discovery.
Diameter: 1.4 Earths
Mass: 4.6 Earth mass
Smallest exoplanet ever discovered
Orbital period: .84 days (that thing is screaming around the Kepler 10)
Harbors Life?: Highly improbably (no, not even arsenic-based life!)
Following the announcement, NASA/Kepler held a chat with Kepler Mission expert, Natalie Batalha. It was open to anyone who wanted to join in, and I noticed about 250 participants during the event. There were some great questions and answers, and a full transcript should be up within a couple of days.
I collected a few questions and answers to keep you interested while we wait:
Q: Can Kepler determine anything about the chemical content of a candidate planet’s atmosphere to determine if it would be suitable for life as we know it?
Natalie: Kepler can not probe the atmosphere of the planet, no. However, I fully expect other telescopes and missions to do transmission spectroscopy to see if it has an atmosphere. With transmission spectroscopy, you observe the planet when it is right in front of the star (allowing starlight to stream through its atmosphere) and then you observe it when it is not in front of the star. Then, you compare the two to see what the atmosphere might have done to the starlight.
Q: How do you measure the planet mass, size and the distance to the star? And the planet composition?
Natalie: Mass comes from the Doppler measurements of the wobble of the star as the planet/star orit about their commone center of mass. Radius comes from the amount of dimming of starlight that occurs during transit. The distance can be derived if you know the surface temperature and radius of the star. Together they give the intrinsic brightness. We know how bright the star appears to us. Knowing how right it SHOULD be instrinsically allows us to determine how far away it is — 560 light-years for Kepler-10.
Q: What are the prospects for additional planets in the Kepler 10 star system? Any hints?
Natalie: There is actually already a very compelling signature of another potential planet in this system. There is a transit event that recurs once every 45 days and is suggestive of a planet a bit larger than 2 times the radius of the Earth.
The Kepler Mission is a wonderful tool to unlocking our understanding of planets outside our own solar system. It’s an exciting time to be on the one known planet (so far!) that allows us to enjoy it.Continue Reading »
NASA’s Kepler mission will be holding a press conference tomorrow, to make an announcement about a “new planet discovery”.
From the Kepler website:
A new planet discovery will be announced Monday Jan. 10 during the ‘Exoplanets & Their Host Stars’ presentation at the American Astronomical Society (AAS) conference in Seattle, Washington.
Natalie Batalha of the NASA Kepler Mission Team will be online answering your questions about this new planet finding on Monday, Jan. 10 from 3:30 p.m. to 4:30 p.m. EST / 12:30 p.m. to 1:30 p.m. PST. Natalie will be chatting with you live from the conference in Seattle.
The chat can be found at this website.
To summarize the mission, Kepler is a space-observatory –launched in 2009 — designed to discover Earth-like planets orbiting other stars. It has a planned mission lifetime of 3.5 years. Kepler measures light from stars, and watches for dimming which could indicate a planet transiting in front of the star. Many of the stars Kepler has observed have been variable stars — stars whose brightness changes naturally, as opposed to anything blocking some of its light. These variable stars are dropped from the target database, and replaced with new candidates.
What types of exoplanets is Kepler looking for specifically? According to the Kepler mission page:
The challenge now is to find terrestrial planets (i.e., those one half to twice the size of the Earth), especially those in the habitable zone of their stars where liquid water and possibly life might exist.
The Kepler Mission, NASA Discovery mission #10, is specifically designed to survey a portion of our region of the Milky Way galaxy to discover dozens of Earth-size planets in or near the habitable zone and determine how many of the billions of stars in our galaxy have such planets.
So far, Kepler has found more than 700 planet candidates, which require further data-analysis and ground-based observations to rule out any “false signatures”. Kepler has 8 confirmed planets. These have ranged in mass from 7.7% to more than double the mass of Jupiter. For comparison, Jupiter is 317 times more massive than the Earth — or, Earth is .3% the mass of Jupiter.
So, we wait until tomorrow (or today for many of you) to find out the details of our newly discovered exoplanet friend.Continue Reading »
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!Continue Reading »