Inspecting nuclear warheads like they were passwords

Nuclear weapon inspectors have a weighty but tricky job. An inspecting state relies on them to verify if a weapon is a nuclear warhead, but the state whose weapons are being inspected doesn’t want to divulge too much information about the weapon’s design or performance. As David Cliff, a researcher at the Verification Research, Training and Information Center, London writes,

In warhead dismantlement, the objective needs to be to gain as much confidence through agreed verification measures as possible, thereby minimizing the extent to which trust [between the two states] will need to become a factor… In fact, as a means of building trust and confidence between states, dismantlement is of limited value unless it occurs in a transparent and verifiable manner.

(Emphasis mine)

So, on the one hand, transparency is needed to ensure the number of warheads have been reduced. On the other, secrecy is necessary to keep the warheads from reaching the hands of potential adversaries, not to mention to ensure deterrence. Methods to measure sensitive information often include safeguards to protect it, adding another layer of liability.

To simplify this process, researchers from the USA and UK have developed a new technique to verify warheads without needing any sensitive information about them – thus eliminating the need for them to be made available in the first place. They propose to bombard a supposed warhead with neutrons, then using a detector to check the properties of the particles that have passed through. Next, an actual known warhead is subjected to the same profiling.

Then, an inspector randomly chooses to use each detector on other warheads that need to be inspected. Over multiple tests, the detector will be able to check with increasing likelihood if a warhead is genuine or not by comparing it to previous tests. Crucially, the inspector will not have access to any parameters of the comparison but only if a ‘Yes’ or a ‘No’ has been signalled.

A paper describing this ‘zero-knowledge protocol’ appeared in Nature on June 26, in which the researchers argue,

This technique will reveal no information about the composition or design of nuclear weapons when only true warheads are submitted for authentication, and so does not require an engineered information barrier.

To assist in their analysis, the team used the unclassified British Test Object (BTO), which “does not contain special or other nuclear materials, but is used to develop and calibrate imaging systems for diagnostic analysis of nuclear weapons”. It consists of concentric rings of polystyrene, tungsten, aluminum, graphite and steel. Over multiple tests (i.e. simulations) on the BTO, the team then estimates the number of tests needed to reliably detect increasingly serious defects, finding 5,000 and 32,000 to be sufficient to detect the most serious ones.

A gamma ray telescope at Hanle: A note

A gamma ray telescope is set to come up at Hanle, Ladakh, in 2015 and start operations in 2016. Hanle was one of the sites proposed to install a part of the Cherenkov Telescope Array, too. A survey conducted in the 1980s and 90s threw up Hanle as a suitable site to host telescopes because “it had very clear and dark skies almost throughout the year, and a large number of photometric and spectroscopic nights,” according to Dr. Pratik Majumdar of the Saha Institute of Nuclear Physics, Kolkata.

The Cherenkov Telescope Array will comprise networked arrays of telescopes in the northern and southern hemispheres to study and locate sources of up to 100-TeV gamma rays. Dr. Subir Sarkar at Oxford University had told me at the time that “the CTA southern observatory will be able to study the center of the galaxy, while the northern observatory [of which the Hanle telescope will be a part] will focus on extra-galactic sources.” Another Cherenkov telescope, called HAGAR, has been in operation at Hanle since 2008, according to Dr. Majumdar.

Artist's conception of the CTA once installed at one of its sites.
Artist’s conception of the CTA once installed at one of its sites. Image: Pratik Majumdar/SINP

Although Hanle was in the running around July 2013, its name was lifted from the list by April 2014. Dr Sarkar had written to me earlier,

“I realize it is interesting to mention to your readers that Hanle, Ladakh is a proposed site. However I should tell you that this is very unlikely – not because the site is unsuitable (in fact it is excellent from the scientific point of view) but because the Indian Govt. does not permit foreign nationals to visit there. I know a French postdoc who was at TIFR for several years and is now working with Pratik Majumdar at SINP … even he has been unable to get clearance to go to Hanle! I do think India needs to be more proactive about opening up to people from abroad, especially in science and technology, in order to benefit from international collaboration. Unfortunately this is not happening!”

This is ‘closedness’ showed up in another place recently: at the INO, Theni.

Dr. Majumdar added,

Almost all the research institutes and installations in India need to pull up their socks particularly in case of dealing with such bureaucratic procedures [of letting foreign scientists move around inside the country]. We do need to change this inhibitive attitude. BARC is another case where bringing in foreigners for work/visits is quite a big hassle and that is not just for foreigners, even any Indian national is not allowed to take laptops/CDs/other electronic items inside BARC without special permissions. This is unthinkable to me in today’s age. So, even though it does not sound very bad always, there are various layers of inhibition where at various levels this has to be fought.

He added that HAGAR operated with similar restrictions. In fact, in 2018, another gamma-ray observatory is set to be installed in Hanle by TIFR and BARC. So we have local scientific institutions asking for more international participation and eager to deliver results, and on the other hand annoying bureaucratic restrictions on those who decide to participate.

Did Facebook cheat us?

'I don't want to live on this planet anymore' meme. Image:
You might want to rethink that.


There were some good arguments on this topic, swinging between aesthetic rebuttals to logical deconstructions. Here are four I liked:

1. Tal Yarkoni, Director of the Psychoinformatics Lab at University of Texas, Austin, writes on his blog,

“… it’s worth keeping in mind that there’s nothing intrinsically evil about the idea that large corporations might be trying to manipulate your experience and behavior. Everybody you interact with–including every one of your friends, family, and colleagues–is constantly trying to manipulate your behavior in various ways. Your mother wants you to eat more broccoli; your friends want you to come get smashed with them at a bar; your boss wants you to stay at work longer and take fewer breaks. We are always trying to get other people to feel, think, and do certain things that they would not otherwise have felt, thought, or done. So the meaningful question is not whether people are trying to manipulate your experience and behavior, but whether they’re trying to manipulate you in a way that aligns with or contradicts your own best interests. The mere fact that Facebook, Google, and Amazon run experiments intended to alter your emotional experience in a revenue-increasing way is not necessarily a bad thing if in the process of making more money off you, those companies also improve your quality of life. I’m not taking a stand one way or the other, mind you, but simply pointing out that without controlled experimentation, the user experience on Facebook, Google, Twitter, etc. would probably be very, very different–and most likely less pleasant.”

2. Yarkoni’s argument brings us to these tweets.

Didn’t get it? Chris Dixon explains.

I didn’t spot these tweets. TechCrunch did, and it brings up the relevant comparison with A/B testing. A/B testing is a technique whereby web-designers optimize user experience engineers by showing different layouts to different user groups, then decide on the best layout depending how which users responded to which layouts. Like Dixon asks, is it okay if it’s done all the time on sites that want to make money by giving you a good time?

You’d argue that we’ve signed up to be manipulated like that, not like this – see #4. Or you’d argue this was different because Facebook was just being Facebook – but the social scientists weren’t being ethical. This is true. To quote from the TechCrunch piece,

A source tells Forbes’ Kashmir Hill it was not submitted for pre-approval by the Institutional Review Board, an independent ethics committee that requires scientific experiments to meet stern safety and consent standards to ensure the welfare of their subjects. I was IRB certified for an experiment I developed in college, and can attest that the study would likely fail to meet many of the pre-requisites.

3. The study that appeared in the Proceedings of the National Academy of Sciences, which it appears not many have read. It reports a statistically significant result that emotions are contagious over Facebook. But as Yarkoni demonstrates, its practical significance is minuscule:

… the manipulation had a negligible real-world impact on users’ behavior. To put it in intuitive terms, the effect of condition in the Facebook study is roughly comparable to a hypothetical treatment that increased the average height of the male population in the United States by about one twentieth of an inch (given a standard deviation of ~2.8 inches).

4. Facebook’s Terms of Service – to quote:

We use the information we receive about you in connection with the services and features we provide to you and other users like your friends, our partners, the advertisers that purchase ads on the site, and the developers that build the games, applications, and websites you use. For example, in addition to helping people see and find things that you do and share, we may use the information we receive about you:

… for internal operations, including troubleshooting, data analysis, testing, research and service improvement.

IMO, the problems appear to be:

  1. The social scientists didn’t get informed consent from the subjects of their experiments.
  2. What a scientific experiment is is not clearly defined in Facebook’s ToS – and defining such a thing will prove very difficult and is likely never to be implemented.

To-do: Find out more about the IRB and its opinions on this experiment.

Science Quiz – June 30, 2014

Every week, I create a science quiz for The Hindu newspaper’s In School product. It consists of 10 questions and only developments from the week preceding its day of publication (Monday). The answers are at the end.

  1. A team of Scottish scientists announced the discovery of the world’s oldest animal-built _____ in Africa in the week of June 23. According to them, they were built by small water animals called Cloudina that existed about 548 million years ago. Fill in the blank with the name of a type of build-up of organic material. In fact, today, the world’s largest single structure made by organisms is also one such ____.
  2. Scientists were able to find out what Neanderthals living in Spain 50,000 years ago ate by studying fossilized remains of their ____. An analysis of a sample of this showed that members of this extinct human species ate mostly meat but also a lot of vegetables. Fill in the blank.
  3. The Milky Way is a spiral galaxy with a supermassive black hole at its center, named Sagittarius A*. On June 26, South African astronomers announced the discovery of a galaxy named SDSS J150243.09+111557.3 some 4.2 billion light-years away from Earth. How many black holes does it contain at its center?
  4. Name the USA-based company that plans to fly passengers toward the uppermost reaches of Earth’s atmosphere in 2016, propelled by a parachute-style balloon attached to a capsule. It plans to charge $75,000 per person for the two-hour trip. Last week, it announced the successful completion of its balloon’s test flight, claiming that it established a world record for climbing to the highest altitude for a vehicle of its type.
  5. On June 26, scientists unveiled the genetic blueprint of the ________ ___, a freshwater animal found in South America that can generate an electric shock of up to 600 volts. Despite what their name suggest, these animals are better related to the catfish, and grow up to 2 meters long. Fill in the blanks.
  6. A new animal has been discovered in western Africa. It looks like a long-nosed mouse, weighs about 28 grams and is about 19 cm long from nose to tail. But don’t let its very small size deceive you: genetic testing of the creature revealed that its DNA is actually related to that of the elephant! Name it.
  7. This is the first rocket designed by Russia since 1991, i.e. after the dissolution of the USSR. On June 27, it was supposed to be launched for the first time when its computers automatically aborted the launch for some reason. After inspection, it was slated to launch on June 28, when it was delayed again. Name it.
  8. What did monkeys evolve to keep those from one species mating with another, according to scientists from the UK?
  9. In the late 17th century, the British scientist Isaac Newton defined a number called the _____________ ________. The exact value of this number corresponds to the strength of a particular force of nature. The value of this number is thought to be constant throughout the universe. Despite its prevalence, however, scientists don’t yet know its exact value. In the week of June 23, Italian researchers announced that they had measured the value of this constant to a new level of precision using a technique different from that used in history. Name the constant.
  10. June 26 was the 190th birth anniversary of this Irish physicist and engineer for whom the SI unit of temperature is named. He contributed extensively to the field of thermodynamics, although he made his wealth and fame by working on the electric telegraph. Name him.


  1. Reef
  2. Feces
  3. Three!
  4. World View
  5. Electric eel
  6. Elephant shrew
  7. Angara
  8. Distinct faces
  9. The gravitational constant
  10. William Thomson, 1st Baron Kelvin (Kelvin is the unit)

Looking for life? Look for pollution.

Four-thousand years on Earth and we’ve a lot of dirt to show for it. Why would an advanced alien civilization be any different?

That’s the motivation that three astrophysicists from Harvard University have used to determine that powerful telescopes could look for signs of chlorofluorocarbons (CFCs) in alien atmospheres as signs of alien civilization.

“If the civilization reaches an industrial revolution similar to ours, then the chances are high” of finding CFCs in their atmosphere, Avi Loeb, a member of the study from the Harvard-Smithsonian Center for Astrophysics, told Is Nerd. “In our paper, we are demonstrating the detectability of the related signal if industrial pollution exists in the atmosphere of a planet.”

The team have estimated that NASA’s upcoming James Webb Space Telescope could look for signs of tetrafluoromethane (CF4) and trichlorofluoromethane (CCl3F) in alien atmospheres with a few days’ exposure. However, this is a high opportunity cost for such a powerful telescope, so the trio propose looking for these CFCs if biomarkers like molecular oxygen are found first.

While oxygen, alongside methane and nitrous oxide, points to the possible existence of primitive life, CFCs are almost exclusively anthropogenic.

Absorption spectroscopy

The space telescope will be studying starlight that has passed through an exoplanet’s atmosphere. Molecules of CF4 and CCl3F will absorb photons of light of specific wavelengths, casting a shadow. Astronomers then match the shadows with the molecules.

The team’s pre-print paper says their technique would be suitable for Earth-like exoplanets orbiting white-dwarfs. This is because photons of the wavelengths absorbed by CF4 and CCl3F are available in sufficient quantities from the star. On the downside, methane and nitrous oxide also absorb light along similar wavelengths as CF4, and oxygen and water along similar wavelengths as CCl3F.

Nevertheless, they find that the James Webb Space Telescope could detect the presence of high CF4 and CCl3F concentrations in 3 and 1.5 days respectively. An advantage of looking for CFCs like CF4 is, according to their pre-print paper, its longevity. “[Given] the half-life of CF4 in the atmosphere is [about] 50,000 years … it is not inconceivable that an alien civilization which industrialized many millennia ago might have detectable levels of CF4,” they write.

NASA plans to launch the space telescope, successor to the Hubble, in 2018. By then, it will be one of the next generation of telescopes (diameter in the range of 24-40 meters), each of which could look for signs of alien civilization using the Harvard team’s technique. “They include the Giant Magellan Telescope, the European Extremely Large Telescope, and the Thirty Meter telescope,” Dr. Loeb said.

Of them, the Giant Magellan is planned to a have a dedicated instrument called G-CLEF with exceptional spectroscopic capabilities, he added. Construction for the Extremely Large Telescope began last week in Chile.

Blogging at NYTimes and The Hindu

I’m going to draw some parallels here between the The New York Times and The Hindu in the context of Times’s decision to shut or merge up to half of its blogs (Disclosure: I launched The Hindu Blogs in December 2012 and coordinated the network until May 2014). This is not about money-making, at least not directly, as much as about two newspapers faced with similar economic problems at vastly different scales confronting the challenges of multi-modal publishing. Times’ decision to move away from blogs, which was brought to wider attention when Green went offline in March 2013, is not to be confused with its rejection of blogging. In fact, it’s the opposite, as Andrew Beaujon wrote for Poynter:

Assistant Managing Editor Ian Fisher told Poynter in a phone call: “We’re going to continue to provide bloggy content with a more conversational tone,” he said. “We’re just not going to do them as much in standard reverse-chronological blogs.”

This is mixed news for blogs. The experimental quality in the early days of blogging – which blogs both fed and fed off – is what inspired many post formats to emerge over the years and compete with each other. This competition was intensified as more news-publishers came online and, sometime in the late 2000s, digital journalism knew it was time for itself to take shape. The blog may have been fluidly defined but its many mutations weren’t and they were able to take root – most recognizably in the form of Facebook, whose integrated support for a variety of publishing modes and forums made the fluidity of blogging look cumbersome.

The stage was set for blogs to die but in a very specific sense: It is the container that is dying. This is good for blogs because the styles and practices of blogging live on, just the name doesn’t. This isn’t only a conceptual but also a technical redefinition because what killed blogs is also what might keep the digital news-publishing industry alive. It’s called modularization.

The modular newsroom

While I was at The Hindu, I sometimes found it difficult to think like the reader because it was not easy to forget the production process. The CMS is necessarily convoluted because if it aspires to make the journalist’s life easier, it has to be ‘department’-agnostic: print, online, design and production have to work seamlessly on it, and each of those departments has a markedly distinguished workflow. There is that obvious downside of ponderousness but on such issues you have to take a side.

One reason Beaujon cites for Times’ decision is their blogs’ CMS’s reluctance to play along with the rest of the site’s (which recently received a big redesign). I can’t say the problem is very different at The Hindu. In either institution, the management’s call will be to focus the CMS on whichever product/department/service is making the biggest profits (assuming one of them does that by a large margin) – and blogs, despite often being the scene of “cool” content, are not prioritized. The Schulzbergers have already done this by choosing to focus on one product while, at The Hindu, Editor Malini Parthasarathy has in the last two months ramped up her commitment to its digital platform with the same urgency as could have been asked of Siddharth Varadarajan had he been around.

The reason I said the demise of the container was also technical because, in order to keep a department-agnostic CMS both lightweight and seamless (not to mention affordable), larger organizations must ensure they eliminate redundant tasks by, say, getting a “print” journalist to publish his/her story online as well. Second, the org. must also build a CMS focused on interoperability as much as intra-operability. Technically speaking, each department should be an island that communicates with another by exchanging information formatted in a particular way or according to some standards.

Fragmenting the news

This is similar to blogs because the fragmentation that helped make it popular is also what has helped establish its biggest competitors, like tumblelogs, Twitter, Snapchat, Pinterest, etc., and each of these modes in turn are inspiring new ways to tell stories. A more modularized newsroom in the same vein will be able to tell different kinds of stories and be more adaptive to change and shock, not to mention better positioned to serve the fragmenting news. Better yet, this will also give journalists the opportunity to develop unique workflows and ethos to deal specifically with their work. That’s one thing that doesn’t bode well for the unfortunate blogs at the Times: “reintegration” is always accompanied by some losses.

Through all of this, anyway, the good name of “news-site” might become lost but we mustn’t underestimate our readers to not be able to spot the news under any other name.

However, this is where the similarities between the two organizations do end because they operate in drastically different markets. While traffic on both sites mostly entered ‘sideways’, i.e. from a link shared on the social media or on the site homepage instead of from the blogs landing page, what it did for the site itself is different. For one, among the people The Hindu calls its audience, purchasing power is way lower, so the symmetry that the Times might enjoy in terms of ad rates in print and on the web is just almost-impossible to achieve in India. This makes the battle to optimize UX with income grittier within Indian publications. The quality of the news is also nothing to write home about, although there is reason to believe that is changing as it’s less shackled by infrastructural considerations. Consider or Homegrown.

These are, of course, nascent thoughts, the knee-jerk inspired by learning that the Times was shutting The Lede. But let’s not lament the passing of the blog, it was meant to happen. On the other hand, the blog’s ability to preserve its legacy by killing itself could have many lessons for the newsroom.

Restarting the LHC: A timeline

CERN has announced the restart schedule of its flagship science “project”, the Large Hadron Collider, that will see the giant machine return online in early 2015. I’d written about the upgrades that could be expected shortly before it shut down in 2012. They range from new pixel sensors and safety systems to facilities that will double the collider’s energy and the detectors’ eyes for tracking collisions. Here’s a little timeline I made with Timeline.js, check it out.

(It’s at times like this that I really wish would let bloggers embed iframes in posts.)

New results on Higgs bosons' decay into fermions

For a boson to be the Higgs boson, it has to be intimately related to the physical process it was hypothesized in 1964 to help understand. With new results published on June 22, physicists from CERN, the lab that runs the experiments that first discovered the Higgs boson, have found that to be true, further cementing the credibility of their theories as well as discovering more properties that could guide future experiments.

The Higgs boson is too short-lived to be spotted directly. Its lifetime is 10-22 seconds. In this period, it quickly decays into groups of lighter particles. The theory called the Standard Model of particle physics predicts how often the Higgs decays into which groups of particles. Broadly, the rate of this decay is guided by how strongly the Higgs couples to each particle, and such coupling gives rise to the particle’s mass (Note: the Higgs decays only into fundamental particles, not composite particles like protons and neutrons, because it gives mass only to fundamental particles).

The June 22 Letter in Nature Physics describes the champagne bottle boson‘s decay into fermions, the particles that make up all matter. By experimentally finding these rates, physicists accomplish two things. One, they assert the strength of whichever theory predicted these rates – the Standard Model, in this case (the Yukawa couplings, to be specific). Two, they establish that the Higgs boson does couple to fermions and gives them mass. The Letter draws its conclusions from experiments performed in 2011 and 2012.

The third generation of fermions

However, there is a limitation. Because the Higgs weighs 125 GeV, it could only have decayed into lighter fermions, not heavier ones. This means physicists have experimental proof for the Higgs giving mass to fermions lighter than itself; in this case, these are the so-called third generation fermions comprising the bottom quark and the tau lepton. Quarks are fundamental particles that come together to compose protons and neutrons. Leptons are some of the lightest of the matter particles, one common example of which is the electron.

In 2011, the Compact Muon Solenoid (CMS) experimental collaboration, which is the group of scientists that runs the CMS detector, had looked for Higgs bosons decaying into bottom quark-antiquark pairs. At this time, the Large Hadron Collider, which produces these particles by smashing protons together at high speeds, was operating at an energy of 7 TeV – i.e. each beam of protons coming into the collision had an energy of 7 TeV. The consequent results were published in January this year. The 2012 results concerned the search for Higgs bosons’ decays into tau lepton-antilepton pairs at 8 TeV. The pre-print paper submitted to arXiv is here (link to published paper).

The search for these particles is compounded by the fact that they aren’t just produced by the decaying Higgs boson but by a profusion of other Standard Model processes. The scientists at CERN use a combination of statistical techniques to single out which processes produced the particles of interest. They also use as many unique signatures as possible to narrow down their search. For example, the search for the bottom quark-antiquark pair of particles is reconstructed based on a Higgs boson being produced together with a W or a Z boson, whose decays have their own signatures.

The significance at which they report each decay process is in this table, picturized below.

Summary of results for the Higgs boson mass hypothesis of 125 GeV.
Summary of results for the Higgs boson mass hypothesis of 125 GeV.

The Letter, as you can see, is open access, as are all the papers linked to in it.

Science Quiz – June 23, 2014

Every week, I create a science quiz for The Hindu newspaper’s In School product. Although it is geared exclusively at school students, it should be available for adults as well because it’s a great place to find the news packaged plain and simple. The quiz consists of 10 questions and only developments from the week preceding its day of publication (Monday). The answers are at the end.

  1. The construction of the world’s biggest optical telescope began on June 19. It’s called the European Extremely Large Telescope, being built by the European Southern Observatory. Name the country in which it is being built.
  2. How big can a galaxy get? Astronomers are not sure, but on June 20, they announced that they had found evidence to believe its size might be controlled by the size of the ____________ _____ _____ at its center. Fill in the blanks with the name of an object whose gravitational pull is so strong, even light can’t escape it.
  3. In the week of June 16, a bunch of NASA scientists announced that they had used the Spitzer space telescope to measure the size of an asteroid named 2011 MD. This asteroid is one of the three candidates the space agency plans to pull out of its location and into an orbit around the moon so astronomers can study it better. In which part of the electromagnetic spectrum does the Spitzer space telescope observe the universe?
  4. What is the name of NASA’s mission to drag an asteroid into an orbit around the moon? The agency plans to execute this mission by 2025.
  5. Name the Canadian company that claims to manufacture the world’s only quantum computers. These computers have been mired in controversy even until June 20 because many scientists claim these computers are not faster than conventional computers even though their name implies they’re supposed to be.
  6. Name the American chemist who invented a polymer named Kevlar in the 1960s. Kevlar is used in bullet-proof vests because, weight for weight, it is five times stronger than steel and adept at slowing down bullets and shrapnel. The inventor herself won her country’s National Medal of Technology in 1996 for her work that has helped save thousands of lives. She died on June 20 at the age of 90.
  7. _______ commonly eat other insects. On June 19, however, an Australian scientist announced that there was evidence that many species of them also ate fish and that, in fact, such species were found on all continents except Antarctica. Fill in the blank with the name of an insect that is the seventh most diverse organism on the planet.
  8. The International Space Station will get its first ______-_____ in November. It is being made by an Italian company named Lavazza, which announced its plans on June 17. Fill in the blanks (think small).
  9. Name the NASA spacecraft that will go beyond the orbit of Neptune in August 2014, and become the first fully-operational human-made object to go that far.
  10. Name the French physicist and philosopher after whom the unit of pressure is named. His 391st birth anniversary was on June 19, 2014.


  1. Chile
  2. Supermassive black holes
  3. Infrared
  4. Asteroid Redirect Mission
  5. D-Wave
  6. Stephanie Kwolek
  7. Spiders
  8. Coffee-maker
  9. New Horizons
  10. Blaise Pascal

Spitzer has helped choose a near-Earth object the A.R.M. could bring nearer

From its perch up in space, Spitzer can use its heat-sensitive infrared vision to spy asteroids and get better estimates of their sizes.

This is what the author of a study that appeared in Astrophysical Journal Letters on June 19 said in a NASA press release about the space telescope. The Spitzer was used by a group of astronomers that authored the paper to study the dimensions and other physical properties of an asteroid named 2011 MD. They’ve found it to be suitable for NASA’s purpose, i.e. to bring a near-Earth object (NEO) into an orbit around the moon and study it – all by the 2020s. This elevation to suitability also makes 2011 MD the third such candidate NASA will consider as it ramps up the mission, dubbed the Asteroid Redirect Mission (ARM).

This image of asteroid 2011 MD was taken by NASA's Spitzer Space Telescope in Feb. 2014, over a period of 20 hours. The long observation, taken in infrared light, was needed to pick up the faint signature of the small asteroid (center of frame). The Spitzer observations helped narrow down the size of the space rock to roughly 20 feet (6 meters), making it one of a few candidates for NASA's proposed Asteroid Redirect Mission for which sizes are approximately known.
This image of asteroid 2011 MD was taken by NASA’s Spitzer Space Telescope in Feb. 2014, over a period of 20 hours. The long observation, taken in infrared light, was needed to pick up the faint signature of the small asteroid (center of frame). The Spitzer observations helped narrow down the size of the space rock to roughly 20 feet (6 meters), making it one of a few candidates for NASA’s proposed Asteroid Redirect Mission for which sizes are approximately known. Image: NASA/JPL-Caltech/Northern Arizona University/SAO

Why was Spitzer used? From the release:

Prior to the Spitzer study, the size of 2011 MD was only very roughly known. It had been observed in visible light, but an asteroid’s size cannot be determined solely from visible-light measurements. In visible light alone, for example, a white snowball in space could look just as bright as a dark mountain of cosmic rock. The objects may differ in size but reflect the same amount of sunlight, appearing equally bright.

The advantage that infrared light presents, on the other hand, is that it reveals the body’s temperature, mass and density. Subsequently, the study’s authors were able to conclude that 2011 MD is lighter than asteroids usually are, and is possible two-thirds hollow. This, they think, could be because it is actually a collection of rocks or is one rock surrounded by debris. One more thing about this new candidate for ARM is its odd, oblong shape.

The team says the small asteroids probably formed as a result of collisions between larger asteroids, but they do not understand how their unusual structures could have come about. They plan to use Spitzer in the future to study more of the tiny asteroids, both as possible targets for asteroid space missions, and for a better understanding of the many asteroid denizens making up our solar system.

Knowing the size of the NEO to bring closer is important because it will help NASA plan the “how” of the mission. In another press release yesterday, the space agency said it was awarding $4.9 million to 18 proposals each of which described a method to execute the ARM, over a period of six months. NASA started accepting these proposals in March this year and reportedly received 108. Two names quickly jump out from among the proposals:

  • Deep Space Industries, which announced in January 2013 that it plans to scout for a near-Earth object, mine a small sample from it, and return that to Earth by 2016. The press release states that, through the ARM, DSI wants to “examine public-private partnership approaches”.
  • Planetary Society, which wants to put bacteria on the asteroid retrieval vehicle to “transport extremophiles through deep space and return them to Earth to test panspermia and astrobiology.”

The 2011 MD press release is available here, and the one about the proposals, here.