Very interesting: a map of small asteroid impacts with the atmosphere


Credit: NASA

Small near-Earth asteroids, around a meter in size, hit our atmosphere and disintegrate around every other week. We now know this because “U.S. sensors” can, and do, detect and measure the energy released by these detonations. As this NASA Web story reports, an unidentified source (you figure it out…) has given the agency 20 years worth of data collected by (ahem) “U.S. government sensors” on “bolide impact events.” These data will be (but aren’t quite yet) available to the scientific community for research. What’s a bolide, and what are bolide impact events? See this NASA Web page for information. Also see this story by Leonard David about the “fireball” site, which he said went up March 1, 2013. Back to the “newly released data.” These twenty years worth of observations show that small asteroid impacts with Earth’s atmosphere are “frequent and random.” A map of these small impact events shows the frequency of, and energy released by, impacts detected from 1994 through 2013. “Over this 20-year interval,” NASA says, “U.S. Government assets recorded at least 556 bolide events of various energies.” The sizes of the dots are indicative of the amount of “optical radiated energy” released, measured in billions of Joules (GJ).   Orange dots represent daytime events, and blue dots represent nighttime events. As NASA notes, the largest asteroid impact with the atmosphere during this 20-year interval was the so-called Chelyabinsk event, in which a 20-meter object exploded over Russia on February 15, 2013, releasing the energy equivalent of 440,000 – 500,000 tons of TNT. This is a really interesting story, in my biased opinion (I work as a consultant to NASA’s Near Earth Object (NEO) Observations Program). The map is a particularly striking visual depiction of what’s going on over our heads all the time – largely though not completely without consequences, as the blast wave generated by the Chelyabinsk event shattered glass and damaged buildings over a wide area. The map shows that because these impacts are randomly distributed, about three quarters of them occur over oceans and about half occur during daylight hours. I’d guess that many of these events had few to zero “naked eye” human observers. As NASA’s story notes, “Meteor Crater near Winslow, Arizona, is evidence of the impact with Earth’s surface of a 50-meter asteroid about 50,000 years ago.” I visited Meteor Crater in 2013 – quite impressive (see below).

 LB @ Meteor Crater.3.13

Credit: LA Lewis

I’ll be interested to see what other insights NEO scientists may glean from this rich database. Thanks to “unidentified source” for repurposing these data.

Fireballs, meteors, asteroids, oh my!


A sighting during a Leonid meteor shower. Credit:

A meteor disintegrating in the atmosphere over Texas this past Saturday generated national media coverage and prompted calls to NASA. See CNN’s Nov. 9 report for a quick version of this “fireball” story.

So what is a fireball, anyway? It’s a meteor disintegrating in the atmosphere and making a very visible show of it. The Jet Propulsion Laboratory’s Near Earth Object Program Office offers information on fireballs, also known as bolides. The NEO Program Office also explains the difference between asteroids, meteors, meteoroids, meteors, and meteorites:

“In space, a large rocky body in orbit about the Sun is referred to as an asteroid or minor planet whereas much smaller particles in orbit about the Sun are referred to as meteoroids. Once a meteoroid enters the Earth’s atmosphere and vaporizes, it becomes a meteor (i.e., shooting star). If a small asteroid or large meteoroid survives its fiery passage through the Earth’s atmosphere and lands upon the Earth’s surface, it is then called a meteorite. Cometary debris is the source of most small meteoroid particles. Many comets generate meteoroid streams when their icy cometary nuclei pass near the Sun and release the dust particles that were once embedded in the cometary ices. These meteoroid particles then follow in the wake of the parent comet. Collisions between asteroids in space create smaller asteroidal fragments and these fragments are the sources of most meteorites that have struck the Earth’s surface.”

It seems that people are seeing meteors and fireballs all the time these days….

My explanation for this development is that 1) since the Chelyabinsk event of February 2013 – the spectacular disintegration of a small asteroid in the atmosphere – people are more aware of the phenomena, and 2) due to the ubiquity of smartphones and other handheld imaging and communication devices – not to mention dashcams, which yielded an impressive real-time record of the Chelyabinsk event – information about events such as fireball sightings spreads around the globe in near-real time.

If you’re wondering whether Earth is being bombarded by objects from space these days, the answer is yes. If you’re wondering whether the current situation is unusual, the answer is no. (Stay tuned for more information on the frequency and distribution of bolide impacts with the atmosphere…coming soon….) If you’re wondering whether Earth is at risk of being smacked by an asteroid or comet big enough to cause serious damage, the answer is no, not at the moment, not as far as anybody knows.

So, back to this weekend’s “fireball” event – who you gonna call when you see something you think is a fireball? NASA seems a logical choice, and, indeed, Bill Cooke, head of NASA’s Meteoroid Environment Office, took media calls about the Texas fireball and actually had some data on the event. However, the Meteoroid Environment Office is “responsible for meteoroid environments pertaining to spacecraft engineering and operations,” not – as far as I can tell – explicitly for monitoring fireball sightings 24/7. The objective of this particular NASA office “is to understand the flux and the associated risk of meteoroids impacting spacecraft traveling in and beyond Earth’s orbit.”

Then there’s NASA’s Near Earth Object Observations Program and its program office at JPL (see above). The NEOO program is tasked with finding, tracking, and characterizing NEOs. Again, as far as I can tell, this program is not explicitly tasked with monitoring fireball events 24/7.

Outside NASA, the American Meteor Society, founded in 1911, is a pro-am astronomy group whose members “observe, monitor, collect data on, study, and report on meteors, meteor showers, fireballs, and related meteoric phenomena.” If you want to see where fireballs have been sighted lately, see this group’s website, which offers lots of other information as well.

(Clearly the Internet and social media have dramatically improved professional and amateur astronomers’ ability to share information on these phenomena. Thank you, Mr. President, for taking a step today toward preserving “net neutrality.”)

You can also check out the International Meteor Organization (IMO), “founded in 1988…in response to an ever growing need for international cooperation of meteor amateur work. The IMO has a “fireball” page as well.

If you see what you think is a fireball, you can report it to the AMS or the IMO. See their websites.

Here’s a final thought for the day. I’ve theorized that more people are seeing meteors and fireballs because they are more knowledgeable about the phenomena than they were just a few years ago and because they have the means to record them. It also seems that news-media reports of UFO sightings are mighty scarce these days. Yes, MUFON lives on, and UFOlogy gets plenty of play on infotainment TV channels such as the Discovery Channel, the Learning Channel, the Science Channel (all owned by the multibillion-dollar media mega-corporation Discovery Communications), the History Channel, and Sy Fy. But the mainstream news media don’t seem to be reporting on UFO sightings these days. Could there be a correlation between a better understanding of natural phenomena and fewer claims of alien spaceship visits to Earth?


Advice on asteroid warnings



In a previous post, I reported on the establishment of an International Asteroid Warning Network and the first meeting of IAWN’s steering committee in Boston this past January.

At that meeting, the steering committee decided to hold a workshop on communication issues. That workshop took place in September in Broomfield, Colorado, and a report on the workshop is now available.

As part of my consulting work with NASA’s Near Earth Object Observations Program (NASA is a member of IAWN), I was tasked with organizing this workshop. The Secure World Foundation hosted the workshop, and SWF project manager Laura Delgado Lopez worked with me as my co-organizer, co-facilitator, and report co-author (many thanks, Laura!).

Here are a few of the findings and recommendations that came out of the workshop:

  • Findings:
    • Cultivating and maintaining public trust, issuing notifications and warnings in a timely fashion, maintaining transparency in communications, understanding its various audiences, and planning for a range of scenarios are important to effectively communicate NEO impact hazards and risks.
    • Quantitative and probabilistic scales are of limited value when communicating with non-expert audiences. Qualitative measures of characterizing impact hazards and risks and describing potential impact effects may be more effective communication tools.
    • Employing a common language to communicate about asteroid impact hazards across the different IAWN institutions could help IAWN build its identity and credibility. Establishing mechanisms for routine communication could help increase NEO awareness.
  • Recommendations:
    • IAWN should establish a five-year plan with near and mid-term actions for becoming the global trusted and credible NEO information, notification, and warning network. This plan should consider the fundamental principles of risk communication.
    • IAWN should sponsor briefings and workshops for reporters to improve NEO education within the mass media community.
    • IAWN should develop and employ a new, non-probabilistic scale for characterizing asteroid impact hazards and impact effects. The Broomfield Hazard Scale is proposed for IAWN’s consideration as an impact effects scale.

The IAWN Steering Committee will be meeting in Tucson, Arizona, next week, and members will be briefed on the workshop proceedings there. The steering committee has not accepted, endorsed, or approved any of these findings and recommendations as yet.

I’ve posted the report on this site (see left menu). We made it short on purpose, so people would read it. Please do!

International asteroid warnings: standing up a system?


I’ve posted a report (see left menu) on the results of a recent workshop held to tackle challenges in communicating about near-Earth object (NEO) hazards and NEO impact mitigation.

I was co-organizer and co-facilitator of the workshop and co-author of the workshop report, along with Laura Delgado Lopez of Secure World Foundation (SWF). SWF hosted this workshop, which was organized at the request and for the benefit of the International Asteroid Warning Network (IAWN), an international group of organizations involved in detecting, tracking, and characterizing NEOs. IAWN was organized in response to a United Nations (UN) recommendation and operates independently of the UN.

Our workshop, held in September in Colorado, brought together a diverse group of experts from the NEO science, risk communication, policy, and emergency management communities to provide communication guidance and advice to managers and directors of IAWN member programs and institutions, including NASA and the European Space Agency. (I am a consultant to NASA’s NEO Observations Program on communication issues.)

One interesting recommendation that came out of the workshop is a proposal for a new, non-probabilistic scale for characterizing asteroid impact hazards and impact effects – that is, an impact effects scale.

Even if the NEO community chooses to adopt some sort of impact effects scale, it will still, IMHO, need to work on a better way of characterizing impact probabilities and risks. Many members of this community have come to understand that their Torino and Palermo scales, developed for use among experts, are not especially effective in communicating with non-expert audiences. A major challenge in communicating with non-experts about probabilistic risk assessments is that non-experts may not be cognizant of all the uncertainty surrounding these assessments.

The workshop report has been distributed to members of the IAWN Steering Committee. The Committee has not yet reviewed the report and thus has not yet endorsed or adopted any of the recommendations that came out of the workshop. (See p. 3 of the report for the recommendations.)

Stay tuned.

“Preparing for Discovery”: now on your computer screen


Credit: Library of Congress

For all you curious people who missed it and would like to tune in, the webcast of “Preparing For Discovery,” the Kluge Center/Library of Congress symposium on how we might prepare for the discovery of extraterrestrial life is now archived here.

I posted a preview of the symposium last month.

My talk – “The allure of alien life: from microbes to intelligent life” – is last on the agenda at the link above. (If you listen to it, let me know what you think, yes?) If you want to view my slides or read my full paper, look to the left (”pages”) for a link to them.

I addressed the modern history of public conceptions and perceptions of extraterrestrial life and speculated on how people might respond to the discovery of it. I talked about how pop-culture depictions of “aliens” are not about extraterrestrial life – they’re about us. I talked about the Western-white-male-centric thinking that “otherizes” people who are not like “us” – including fictional intelligent aliens (who are almost always “bad”). And I critiqued what I view as the ideology of the search for extraterrestrial intelligence.

I attended the symposium in its entirety and found it stimulating and thought-provoking. While all talks were interesting, I’ll mention just a few.

Planetary scientist Dirk Schulze-Makuch gave a fascinating talk about the striking diversity of life on Earth, speculating about the sorts of life that might be able to thrive in some extreme extraterrestrial environments, such as his favorite, Saturn’s moon Titan. (His slide show was terrific, check it out.)

Neuroscientist Lori Marino addressed “the landscape of intelligence,” arguing that the current approach to the search for extraterrestrial intelligence – that is, attempting to detect evidence of technology (mainly radio waves) – rests on flawed assumptions. As to what intelligence is, its boundaries are fuzzy, there are no consensus descriptions, and “it doesn’t fit into any theoretical framework.” SETI assumes that human intelligence is the only intelligence we know. And this assumption depends on more assumptions – that human intelligence is unique and that humans are superior to other species.

In a talk entitled “Equating culture, civilization, and moral development in imagining ETI,” anthropologist John Traphagan explained how what we can imagine depends on what we think we know. Our assumptions, beliefs, values, and experiences shape our imaginings. “We” (Western white people) tend to assume that “civilization” —m and definitions of this term are vague – inevitably leads to cultural and moral progress. “There’s little evidence that cultural evolution involves moral progress…. Moral values are cultural products…and they vary dramatically from one culture to another.”

For the record, Traphagan and I were not the only speakers on the agenda who critiqued the Western-white-male-centric thinking that underlies the search for extraterrestrial intelligence…. (It’s the same sort of thinking that underlies rationales for the human exploration, settlement, and exploitation of space, and I continue to be baffled by the Obama administration’s embrace of this old-school ideology.)

The Kluge symposium was organized by Steve Dick, the second Blumberg NASA/Library of Congress Blumberg Chair in Astrobiology (2013-2014). The first Blumberg Chair was David Grinspoon (2012-2013). (I blogged about David’s Kluge symposium last year.) NASA and Kluge did not select anyone to fill the chair for the coming year (2014-2015). Instead, the Kluge Center intends to organize a series of dialogues on astrobiology. We can assume that some sort of announcement will be forthcoming….

Disturbing visions of our future in space


Last week I heard a conversation between a weirdly odd couple about space exploration.

At a meeting in Washington on October 2, science fiction author Neal Stephenson and NASA chief scientist Ellen Stofan shared the stage to talk about their views about the human future in space.

This meeting, “Can We Imagine Our Way to a Better Future?”, was one in a series of “Future Tense” events sponsored by the New America Foundation in partnership with Arizona State University and Slate magazine. The October 2 event was organized around science fiction stories published in a new collection, Hieroglyph: Stories and Visions for a Better Future (HarperCollins, 2014). Neal Stephenson wrote the book’s preface, titled “Innovation Starvation.”

(I don’t know about you, but I don’t believe “we” are starved of innovation. I believe we’re short of the cash required to realize useful visions of change. I also believe that all too often “innovation” means “more” – more resource depletion, more profits for industry, more junk in our garbage dumps….)

The topic of the Stephenson-Stofan dialogue was “Lost in space: how should we approach our future frontier?” (I must note that on the printed agenda, the “frontier” was “final” – on the projection screen, “final” had mutated to “future.”)

“I grew up following the space program as “a heroic quest,” Stephenson began. “There’s a whole generation of bitterly disappointed people from the ‘60s” who haven’t gotten the space colonies and missions to Mars, the goals they dreamed of, he said. “I’m still stuck on the Elon-Musk-style heroic space [effort]. It’s almost an adolescent impulse.” The “inherent destiny” of humankind to expand its presence into space is all the justification I need for a bigger, better space exploration program, he declared. When moderator Patric Verrone (the very funny writer and producer of the very funny TV series “Futurama”) asked whether manifest destiny is enough to justify space exploration, Stephenson said it is.

Stofan said it’s not – “there is scientific justification” as well. Stofan disagreed with the idea that the U.S. space program is “lost in space” without a goal, offering up the James Webb Space Telescope – “unbelievably cool” – and the search for life on Mars. “At NASA we’re feeling like we have a clear goal.”

As for better methods of space propulsion – a major roadblock to more affordable space flight – Stephenson reported that after spending some time trying to come up better alternatives to chemical propulsion, he decided that “it’s almost a waste of time” because so many smart people have been working on the problem for so long, with no results. Stofan responded that NASA’s now investing a lot of effort in developing solar electric propulsion, and she also mentioned the option of nuclear thermal propulsion.

“We as a civilization do great, cool things,” Stofan observed. I can watch astronauts on the International Space Station on my phone, she said – “how cool is that?” She also noted that NASA’s “entering into a new realm,” partnering with the private sector. Someone in the audience commented that commercial interests are not the same as public interests. (Hear, hear.)

Also at this meeting, Tom Kalil, deputy director for technology and innovation at the White House Office of Science and Technology, touted Elon Musk as a role model for innovation. He also touted a paper authored by NASA employees and published last year as “a phenomenally inspiring long-term vision” for the U.S. space program.

Entitled “Affordable, rapid bootstrapping of the space industry and solar system civilization,” this paper (published in the Journal of Aerospace Engineering 26(1), 2013) argues that:

“Advances in robotics and additive manufacturing have become game-changing for the prospects of space industry. It has become feasible to bootstrap a self-sustaining, self-expanding industry at reasonably low cost. Simple modeling was developed to identify the main parameters of successful bootstrapping. This indicates that bootstrapping can be achieved with as little as 12 t landed on the Moon during a period of about 20 years…. The industry grows exponentially because of the free real estate, energy, and material resources of space. The mass of industrial assets at the end of bootstrapping will be 156 t with 60 humanoid robots or as high as 40,000 t with as many as 100,000 humanoid robots if faster manufacturing is supported by launching a total of 41 t to the Moon. Modeling over wide parameter ranges indicates this is reasonable, but further analysis is needed. This industry promises to revolutionize the human condition.”

Indeed, further analysis is needed.

Such developments certainly would “revolutionize the human condition” – but how? What legal and ethical issues must be faced in considering, let alone pursuing, such developments?

The idea that this administration is seriously considering these sorts of wild-eyed visions of exploitation is deeply disturbing.


The allure of alien life: a preview



I’ll be giving a talk on “the allure of alien life” at a symposium at the Kluge Center of the Library of Congress tomorrow. For more information, go to:

(See the page on this site, “The Allure of Alien Life,” for my paper and my slides.)

Today, the first day of this symposium, we heard a vigorous critique of the anthropocentric/ethnocentric/Western-White-Male-centric thinking that dominates the popular and scholarly discourse about the search for extraterrestrial intelligence and speculations about “first contact.”

I guarantee you’ll hear more tomorrow. Tune in. The symposium is being webcast at:

If you miss the live event, the Kluge Center eventually will archive a video recording of the symposium.


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