Tag Archives: Jonathan Amos

A Broader View of Antarctic Glacier Changes

The ice is melting everywhere.

One of the most important questions is what is happening in Antarctica, which has vast amounts of ice, and is subject to complex forces that may be thinning and ultimately melting the ice.  If and when Antarctica fully melts, sea levels will rise tens or meters, which is pretty much the end of the story for human life as we know it.

This spring a group or European researchers report a new analysis of satellite observations that estimates the changes in the grounding lines of glaciers in Antarctica [2].  The grounding line is the border where a glacier first extends out over the ocean.  This line may migrate when ocean water seeps under the glacier, generally due to the bottom of the glacier melting.  Furthermore, glaciers melt faster over water, so grounding lines migrating inland probably indicates the glaciers will be melting faster.

It is difficult to observe conditions deep under the ice, and there are a lot of glaciers in Antarctica.  Some might be melting faster and others not.

The new study used radar altimetry from CryoSat-2, which measures the altitude of the surface of the ice.  Using the instrument to measure the bedrock, ocean, and elevation of the ice, the study developed estimates of the movement of the grounding lines for 34% of Antarctica.  To date, there have been only a few such estimates for limited areas, so this work greatly expands the view of the overall activity.

The BBC produced a nice diagram of how the measurement works.

What Cryosat sees: As the grounding line retreats, the elevation of the ice above lowers, (BBC: CPOM/LEEDS)

The study concludes that most of the glaciers are stable, 10.7% of the Antarctic grounding line retreated and 1.9% advanced faster than 25m/yr. (25 m/yr is the “typical” rate  of retreat since the last glaciation.) This was not the same everywhere, some areas are retreating and some advancing.  But overall, “grounding-line retreat […]coincided with sectors in which ice streams are known to be thinning”.  In fact, the study shows that on average, the grounding-line retreats 110m for every meter the ice thins.

This study is important because it gives a broad view across most of the continent.  This view is particularly important given the variations locally and even in different years.

While these findings are certainly consistent with other data, they also show how important local conditions are.  For example, some areas where the grounding-line is not changing have bedrock topography that holds the water out.  Other areas show large changes in the grounding line in some periods and not others, indicating that local conditions play a strong, if unknown, role.

 

The study confirms general trends but with a much wider and more detailed context. (BBC. CPOM/LEEDS)

 

(I’m not sure that the BBC headline “Antarctica ‘gives ground to the ocean accurately describes the findings.  And who is that supposed to be a quote from?)

This is a neat study, and it shows a great strength of satellite observations to obtain continental scale datasets, even where it is very difficult for humans to visit.

Clearly, there should be corroborating studies from other instruments and, ideally, ground truth.  Not that it will be easy to measure the underside or thickness of these glaciers.


  1. Jonathan Amos, Antarctica ‘gives ground to the ocean’, in BBC News – Science & Environment. 2018. http://www.bbc.com/news/science-environment-43627673
  2. Hannes Konrad, Andrew Shepherd, Lin Gilbert, Anna E. Hogg, Malcolm McMillan, Alan Muir, and Thomas Slater, Net retreat of Antarctic glacier grounding lines. Nature Geoscience, 11 (4):258-262, 2018/04/01 2018. https://doi.org/10.1038/s41561-018-0082-z

 

Space Saturday

 

Jupiter Science from Juno Coming Out

The Juno spacecraft has been in orbit around Jupiter since July 2016, and will complete at least two more orbits under current funding (July, 2018).

One of the goals of the mission is to look in detail at the atmosphere of this gas giant.  From Earth, we can see the stripes, which are vast wind streams (in opposite directions ?!), and the Great Red Spot, the largest hurricane in the solar system. But what is going on under the cloud tops?

After more than a year of data collection, results are starting to come in.  Jonathan Fortney summarizes three new papers appearing this spring in Nature [2].  Fortney points out that Earth bound experiments and  theory have not been able to describe the complicated Hydrogen / Helium atmosphere below the surface we can see.

One study investigated the mass distribution of Jupiter by measuring the Doppler effects on the radio signals from the Juno spacecraft as it swooped past [4].  Fortney notes that this was a very finicky process, which had to account for tiny amounts of acceleration including the absorption and re-radiation of sunlight!  The researchers conclude that the bands we see extend quite deep into the atmosphere.

A second study extends this work to conclude that the strong winds decay slowly down some 3.000 kilometers [5].  I.e., the bands we see probably extend down some 3,000 kilometers into the atmosphere.

A third study finds that below that depth, the planet rotates as a solid [3]. At that depth, the pressure is such that the hydrogen ionizes and electromagnetic forces bind the material into a liquid. (This core is the source of the strong magnetic field.)  Obviously, there must be a very turbulent area at the boundary of these two regions, with huge bands of wind ripping East and West across an inner core.

These studies give a picture of a dense interior, with a deep atmosphere dominated by huge bands of strong winds.  An extremely stormy planet!

See swirling cloud formations in the northern area of Jupiter’s north temperate belt in this new view taken by NASA’s Juno spacecraft. The color-enhanced image was taken on Feb. 7 at 5:42 a.m. PST (8:42 a.m. EST), as Juno performed its eleventh close flyby of Jupiter. At the time the image was taken, the spacecraft was about 5,086 miles (8,186 kilometers) from the tops of the clouds of the planet at a latitude of 39.9 degrees. Citizen scientist Kevin M. Gill processed this image using data from the JunoCam imager.

(Caveat:  these studies are based on the theory of gravitational harmonics which I don’t understand at all.)

Fortney suggests that Juno may be able to make further detailed observations of the Red Spot and other storms, which would be interesting details to have.  He also notes that data returned by the Cassini probe of Saturn should yield comparative measurements for the its less dense and probably deeper atmosphere.

Stay tuned. There is lots of other science coming.

The current funding ends in July, but the mission could continue for several more years if supported.


  1. Jonathan Amos, Jupiter’s winds run deep into the planet, in BBC News – Science & Environment. 2018. http://www.bbc.com/news/science-environment-43317566
  2. Jonathan Fortney, A deeper look at Jupiter. Nature, 555:168-169, March 7 2018. https://www.nature.com/articles/d41586-018-02612-y
  3. T. Guillot, Y. Miguel, B. Militzer, W. B. Hubbard, Y. Kaspi, E. Galanti, H. Cao, R. Helled, S. M. Wahl, L. Iess, W. M. Folkner, D. J. Stevenson, J. I. Lunine, D. R. Reese, A. Biekman, M. Parisi, D. Durante, J. E. P. Connerney, S. M. Levin, and S. J. Bolton, A suppression of differential rotation in Jupiter’s deep interior. Nature, 555:227, 03/07/online 2018. http://dx.doi.org/10.1038/nature25775
  4. L. Iess, W. M. Folkner, D. Durante, M. Parisi, Y. Kaspi, E. Galanti, T. Guillot, W. B. Hubbard, D. J. Stevenson, J. D. Anderson, D. R. Buccino, L. Gomez Casajus, A. Milani, R. Park, P. Racioppa, D. Serra, P. Tortora, M. Zannoni, H. Cao, R. Helled, J. I. Lunine, Y. Miguel, B. Militzer, S. Wahl, J. E. P. Connerney, S. M. Levin, and S. J. Bolton, Measurement of Jupiter’s asymmetric gravity field. Nature, 555:220, 03/07/online 2018. http://dx.doi.org/10.1038/nature25776
  5. Y. Kaspi, E. Galanti, W. B. Hubbard, D. J. Stevenson, S. J. Bolton, L. Iess, T. Guillot, J. Bloxham, J. E. P. Connerney, H. Cao, D. Durante, W. M. Folkner, R. Helled, A. P. Ingersoll, S. M. Levin, J. I. Lunine, Y. Miguel, B. Militzer, M. Parisi, and S. M. Wahl, Jupiter’s atmospheric jet streams extend thousands of kilometres deep. Nature, 555:223, 03/07/online 2018. http://dx.doi.org/10.1038/nature25793

 

Space Saturday

 

Early Light and Signs of Dark Matter?

These are the most interesting times in Astronomy.  In the last century, we have pushed back the history of our Universe to its beginnings, and observed traces of the big bang.  We have discovered black holes, pulsars, and any number of other weird and wonderful things.

Even more interesting, we have only recently discovered that the universe we have been studying is only about 4% of everything out there [3], most of it is “Dark Matter” and “Dark Energy”, which we haven’t figured out how to even see, let alone understand. Wow!  If you don’t think that is cool, I can’t really talk to you.

This month a research team report on observations of another trace of the early universe, from a time when stars were first forming [2]. The study examined radio signals averaged across large areas of the sky, looking for evidence of how the early microwave radiation interacted with the hydrogen in clouds and stars.  This is a pretty finicky measurement to make, but it is indirect evidence from a time that we cannot directly observe.

I am not an astronomer, but I gather that the basic idea is to detect an interaction between early stars, ubiquitous primordial hydrogen, and the cosmic microwave background. This should produce a distortion in the spectrum of the hydrogen, still detectable today (red shifted, and buried in all the other radio signals….).

“After stars formed in the early Universe, their ultraviolet light is expected, eventually, to have penetrated the primordial hydrogen gas and altered the excitation state of its 21-centimetre hyperfine line. This alteration would cause the gas to absorb photons from the cosmic microwave background, producing a spectral distortion that should be observable today at radio frequencies of less than 200 megahertz.” ([2], p.1)

The study found just the predicted distortion, very clearly. However, it is twice as large as predicted by the theory, which suggests that there is a significant missing piece. The discrepancy indicates that the hydrogen was much colder than assumed.

This is an exciting finding, because one possible explanation for the discrepancy is some form of interaction between dark matter and the hydrogen.  If this can be confirmed, it is new information about dark matter, and also a new understanding of the universe at this primordial time.

Possibly most important of all, if this really is an interaction between dark matter and hydrogen, it is something we haven’t seen before.  This may be a hint that we can actually detect dark matter, and that would be H-U-G-E, huge.

The published report is notable for the fact that much of the text is careful analysis of possible errors and alternative explanations.  The team spent two years trying to eliminate possible sources of error, and to come up with possible theoretical explanations [1]. This includes using multiple instruments, multiple configurations, multiple data processing workflows, and many simulations of possible errors.  They also have thought hard about any possible alternative explanations for the findings.

This result is very significant, so there will be efforts to replicate and confirm the findings. The researchers note several projects that may be able to replicate the findings, as well as some future studies that may be possible.  One interesting suggestion is to repeat the measurements from the far side of the moon, using Luna as a shield from the cacophonous radio noise spewing from Earth.  This would be a moon mission that would be worth way more than sending humans to either the moon or mars.  (Are you listening, Elon Musk?)

Finally, I’ll note that this is yet another example of why we need to actually make observations and collect data.  All the theory in the world means very little without empirical evidence, and careful observation almost always finds unexpected things.  In this case, the facts seem to show a huge question mark for theorists to fill.

Cool.


  1. Jonathan Amos, Signal detected from ‘cosmic dawn’, in BBC News – Science & Environment. 2018. http://www.bbc.com/news/science-environment-43200277
  2. Judd D. Bowman, Alan E. E. Rogers, Raul A. Monsalve, Thomas J. Mozdzen, and Nivedita Mahesh, An absorption profile centred at 78 megahertz in the sky-averaged spectrum. Nature, 555:67, 02/28/online 2018. http://dx.doi.org/10.1038/nature25792
  3. Richard Panek, The 4 Percent Universe: Dark Matter, Dark Energy, and the Race to Discover the Rest of Reality, Boston, Houghton Mifflin Harcourt, 2011.
  4. The Dark Energy Survey. Home – The Dark Energy Survey. 2017, https://www.darkenergysurvey.org/.

 

Space Saturday

Dormant Microbes on Mars?

I’m as much of a geeky space enthusiast as the next nerd, and I still want to find evidence of life beyond Earth. I still think there is life out there, even though there is no sign yet.

But after decades of faithful geeking, I’ve gone rather off Mars.  It’s close by, it’s really similar to Earth. It had water on the surface ‘recently’, and likely has ice underground.  But we’ve been watching closely for more than a century, and there is still no evidence of life, or even that life once existed there. By now, if we do find something, it’s likely to be pretty small beer.

(Let’s go to Titan, Enceladus, and the other ice worlds—that’s where we’ll find the coolest stuff, IMO.)

The problem with Mars is that it is too cold, too airless, and way, way too dry.  Granted, it’s at the boundary of what Earth life could conceivably handle, and people are still exploring that boundary, in the hope that something might be hanging on the edge of the cliff.

This winter a team led from Technical University Berlin report a detailed study of one of the most “Martian” terrains on Earth, the Atacama desert in Chile [2].  Home to important telescope projects, the Atacama is high and dry and cold.  Not mush lives there except human scientists, who thrive under the cloudless and dark skies.

Any microbes that live in the Atacama must not only adapt to salty, cold, high UV environment, it is likely to go dormant for long dry periods, waking up when water is available. So, if there are microbes that are inactive most of the time, the fact that we haven’t seen much isn’t conclusive. The new study amassed an array of data that shows that there is a population of microbial life in the soil, even if we haven’t directly encountered them [2].

Much of the report documents just how ‘Martian’ the area is. Little water, lots of accumulated salts, high UV from unfiltered sunlight.  The areas inland get rain every decade or so (though there was a lucky rainstorm during the study period.)

It is important to note that one of the tricky things is to identify microbes that have dropped in from elsewhere from any that live permanently in the area. The study collected a number subsoil samples which are relatively isolated.

The study basically assayed the DNA found in the soils, comparing to profiles in other soils. They identified ‘live’ and ‘dead’ DNA. The former indicates living populations, the latter reflects living populations in the recent past. The reserchers also measured endospores, which are characteristic of dormant but potentially viable microbes.  Finally, the study measured a variety of metabolites, indicators of active life.

The overall results showed that, as would be expected, the biomass is considerably less in the more arid samples.  But even the driest samples showed evidence of episodic populations of microbes.

“our study shows that even the lowest precipitation levels on Earth can sustain episodic incidences of microbial activity.” (p.5)


This is a really neat bit of work.  This sort of multi-method, multi-measurement investigation is a very promising path toward understanding not only Atacama but many other environments.

Of course, this research was motivated by interest in the possible ecologies of Mars.  Sigh.

“The insights gained from the hyperarid core of the Atacama Desert can serve as a working model for Mars, where environmental stresses are even harsher. If life ever evolved on Mars, the results presented here suggest that it could have endured the transition from the early aquatic stage, through increasing aridity cycles, and perhaps even found a subsurface niche beneath today’s severely hyperarid surface.”

Well, maybe.

But honestly, I don’t see that any current Earth environment is actually much of a model for current Mars.  There is no rain at all on Mars. There may be a few places underground that see water episodically, but we don’t know of anything.  Basically, the best case on Mars is akin to the worst case on Earth.  And, most important of all, on Earth there is a gigantic reservoir of life outside the Atacama that has colonized and continues to colonize the ‘worst case’ areas.  Martian life would have to make it on its own.

As the researchers say, Atacama might be a model for the first period of a dessicating Mars. If there once were microbial life, it might have survived in episodic colonies as the planet dried out.  But when the episodes become centuries or millennia apart, all bets are off.

Are there wet episodes on Mars today?  And if so, how often do they happen?  If the annual growth and melting ice caps are associated with a kind of underground ‘rainy seasons’, then maybe microbes could have adapted to live there. That would be interesting to find out—especially to learn if any such microbes are independent or related to life on Earth.

But I guarantee that they won’t resemble the Atacama very closely, because they have not been fed by billions of years of invasions from the hot, wet, lowlands of Earth.


  1. Jonathan Amos, Atacama’s lessons about life on Mars, in BBC News – Science & Environment. 2018. http://www.bbc.com/news/science-environment-43215617
  2. Dirk Schulze-Makuch, Dirk Wagner, Samuel P. Kounaves, Kai Mangelsdorf, Kevin G. Devine, Jean-Pierre de Vera, Philippe Schmitt-Kopplin, Hans-Peter Grossart, Victor Parro, Martin Kaupenjohann, Albert Galy, Beate Schneider, Alessandro Airo, Jan Frösler, Alfonso F. Davila, Felix L. Arens, Luis Cáceres, Francisco Solís Cornejo, Daniel Carrizo, Lewis Dartnell, Jocelyne DiRuggiero, Markus Flury, Lars Ganzert, Mark O. Gessner, Peter Grathwohl, Lisa Guan, Jacob Heinz, Matthias Hess, Frank Keppler, Deborah Maus, Christopher P. McKay, Rainer U. Meckenstock, Wren Montgomery, Elizabeth A. Oberlin, Alexander J. Probst, Johan S. Sáenz, Tobias Sattler, Janosch Schirmack, Mark A. Sephton, Michael Schloter, Jenny Uhl, Bernardita Valenzuela, Gisle Vestergaard, Lars Wörmer, and Pedro Zamorano, Transitory microbial habitat in the hyperarid Atacama Desert. Proceedings of the National Academy of Sciences, 2018. http://www.pnas.org/content/early/2018/02/20/1714341115.abstract

 

PS.  Another good name for a band:

The Possible Ecologies of Mars

Tracking World Fisheries

The oceans are the last preserve of large scale human hunting. Fishing vessels harvest vast amounts from wild fisheries, just as humans have since the Pleistocene. Until recently, there has been little useful data about this huge global industry, even as it hunts species to extinction.

This winter a research team from several institutions report on the “global footprint of fisheries” [2].  Using data from the widely deployed automatic identification system (AIS), they collected movements of tens of thousands of vessels around the world.  The AIS is a safety system that broadcasts id, position, and movements to other nearby ships.  The research used an archive of 22 billion AIS records over four years to estimate where and how fishing occurred.

The research used machine learning to identify movement patterns to imply the type of vessel, type of fishing activity, and when and where fishing happened.  (With 22 billion data points, machine learning can be quite effective!)

The results confirm that there is a lot of fishing out on the ocean.  The (incomplete) data shows fishing in something like 55% of the ocean, with intense fishing in waters close to large industrial nations.  The authors believe this estimate is likely low, but is still much higher than the percentage of land area and total area used for agriculture and grazing.

While the spatial pattern is global and correlated to ocean geography, the temporal patterns were dominated by cultural and political rules.  The study “detected” weekends and holidays in the dataset, and sometimes the effects of fuel prices (if not subsidized).  In contrast, there was comparably little relation to seasonal conditions.  In short, the fishing fleet is clearly a land based operation, dancing to the tune of the sailors’ home countries.

Overall, ocean fishing yields something like 2% of total food for humans. This harvest uses a gigantic amount of space, and relatively large about of energy.  (The study records the travels of ships that amount to 600 trips to the Moon and back.)  One has to wonder about the sustainability of such an activity.

The data in this study are clearly incomplete.  Most smaller fishing vessels are not equipped with AIS at all, and some areas may have poor satellite coverage of the AIS signals.  However, the data do cover a large proportion of the largest ships, and probably is a solid sample for off shore fishing.

It is interesting to see the detailed picture that can be constructed from the relatively simple positioning data from AIS.  I’m pretty sure this data is already in use by law enforcement and other monitoring, and could very well be used to enforce rules about not only location and amounts, but also fishing methods.  For example, these data might be overlaid on maps of species distributions, to understand and control collateral damage to threaten species or areas [1].

This study certainly reminds us about the increasing privacy concerns over personal electronics and smart vehicles, which generate similar data.  Even simple AIS data can identify then and how ships are working, as well as detecting cultural activities such as weekends and Chinese New Year.

It will be interesting to follow this data in the future, as fisheries are exhausted and the human horde shifts to try to find its harvest.  In the next couple of decades, we should be able to get a very clear picture of what may be the last gasp of Pleistocene hunting and gathering.


  1. Jonathan Amos, World’s fishing fleets mapped from orbit, in BBC News – Science & Environment. 2018. http://www.bbc.com/news/science-environment-43169824
  2. David A. Kroodsma, Juan Mayorga, Timothy Hochberg, Nathan A. Miller, Kristina Boerder, Francesco Ferretti, Alex Wilson, Bjorn Bergman, Timothy D. White, Barbara A. Block, Paul Woods, Brian Sullivan, Christopher Costello, and Boris Worm, Tracking the global footprint of fisheries. Science, 359 (6378):904, 2018. http://science.sciencemag.org/content/359/6378/904.abstract

 

El Nino Is Melting Antarctica Ice

Is Antarctica melting?

This may be the most important scientific question facing humanity.  If (when) the southern ice cap melts, it’s pretty much all over for human civilization.

So, there is a lot of attention to measuring and modelling Antarctica these days.


One of the outstanding questions is the effects of warmer climate. Warmer oceans and air generally mean more precipitation, which means more snow in Antarctica.  At the same time, warmer water and air melts sea ice and glaciers along coasts, which means less ice in Antarctica.  In addition, there are relatively short term changes, such as the El Nino cycles, which warm and cool in different years.

In short, there are plusses and minuses to the snow and ice every year, and Antarctica is a big place, where more than one thing happens.  What is the overall trend of the ice cover?

There is only one way to find out, and that is to actually measure the ice and snow. And the only reasonable way to measure a whole continent is with Earth observing satellites.


This winter a team of scientists working at NASA’s Jet Propulsion Lab and other institutions report on a study that combined data from four ESA satellites to create a record of the ice depth in West Antarctica for the last 23 years. These measurements are from radar on the orbital satellite, which, in combination with careful measurement of the satellite position, gives a measure of the top of the ice.

Diagram of Cryosat-2 Instruments

The research team further adjusts the measurements for atmospheric pressure and buoyancy, to derive as accurate a measure as possible for 30 x 30 km patches over the period 1994 – 2017.  These measures are correlated with other data representing the wind, ocean, and other weather.

The research finds that, over the period of the study, the ice has been steadily thinning, likely due to incursions of warmer ocean water under the ice shelf.  Accounting for the general trend, the study examined the effects of the El Nino and Southern Oscillation.  These periodic events intensify surface snow accumulation and ocean-driven basal melting.  The combined result is “an overall height increase, but net mass loss”, because the basal ice lost is denser than the fresh snow.

In El Nino years, this effect adds to the long term trend, and in El Nina years, there is a slowing of ice loss.  If such oscillations become more frequent, intense, or longer, there could be profound effects on the West Antarctic Ice.

The researchers note that these multi year trends can only be observed by continuous satellite coverage, i.e., a series of missions lasting decades.  Unfortunately, the US has dropped its coverage, and ESA’s Cryosat-2 will end in a couple of years.  We are going blind to what is happening in this crucial part of the world.


  1. Jonathan Amos, El Nino’s long reach to Antarctic ice, in BBC News – Science. 2018. http://www.bbc.com/news/science-environment-42614412
  2. F. S. Paolo., L. Padman, H. A. Fricker, S. Adusumilli, S. Howard, and M. R. Siegfried, Response of Pacific-sector Antarctic ice shelves to the El Niño/Southern Oscillation. Nature Geoscience, 2018/01/08 2018. https://doi.org/10.1038/s41561-017-0033-0

 

Space Saturday

 

New Studies About The Chicxulub Asteroid Impact

As everyone knows, there was a large impact at what is now the Gulf of Mexico (the Chicxulub impact) at the exact time that the non-avian dinosaurs died out .  What we don’t really know, though, is how such an impact could wipe out so many species around the globe. It was a big hit for sure, but not necessarily that big.   And, don’t forget that the avian dinosaurs and lots of other species did survive.

The outer rim (white arc) of the crater lies under the Yucatan Peninsula itself, but the inner peak ring is best accessed offshore. Image credit: NASA

There are various ideas about what might have happened. Perhaps the body was a comet, with a lot of gook in the slush. Perhaps the dinosaurs were on the edge of extinction anyway, and the impact was a coincidence that finished them off.  Perhaps there were fires and volcanoes, that created a ‘nuclear winter’ for a century or more. (There is a layer of soot, indicating something like that.)

This year there have been a series of detailed analyses of the Chicxulub Impact Event (and wouldn’t that be a great name for a band!). Much of the new analysis comes from a drilling expedition sponsored by ECORD, the European Consortium for Ocean Research Drilling, Expedition 364 Chicxulub K-Pg Impact Crater“.  (There is no substitute for actual field research, no?)

 The impact was in shallow water, and therefore gouged out a huge amount of the sea floor, which filled the atmosphere with dust [2]. This could have released hundreds of gigatons of CO2 and other chemicals, which could have caused decades of cooling and even longer lasting acidification of the oceans  [3].

This fall, a Japanese team suggested that the area of the impact had a relatively high concentration of hydrocarbons in the rock, resulting in an especially large fireball and huge amounts of soot in the atmosphere [5].

And so on.

I’m no expert on geology or climate modelling, so I can’t really dissect these ideas in detail.

There doesn’t seem to be much disagreement that there was a big boom, with tsunamis and huge forest fires, and very probably earthquakes and volcanoes.  (The Earth ‘rang like a bell’ as one geologist told me.)  For decades after the hit, it looks like there was global cooling and other climate changes—a ‘nuclear winter’ scenario, which killed plants and land animals, and profoundly changed life in the oceans.

It’s clear enough that a Chicxulub scale impact is very bad news for a planet.

But it’s still not clear why the dinosaurs were wiped out everywhere, while plenty of other species survived, including ancestors of birds, frogs, fish, and mammals which lived side-by-side with dinosaurs.

But these new and more detailed studies are giving us a lot to work with.  Combined with more and more fossil evidence, we may be able to come up with some ideas about what combination of luck, geography, physiology, and who knows what may have influenced who died out and who survived Chicxulub.


  1. Jonathan Amos, Asteroid impact plunged dinosaurs into catastrophic ‘winter’, in BBC News – Science & Environment. 2017. http://www.bbc.com/news/science-environment-41825471
  2. Jonathan Amos, Dinosaur asteroid hit ‘worst possible place’, in BBC News – Science and Environment. 2017. http://www.bbc.com/news/science-environment-39922998
  3. Natalia Artemieva, Joanna Morgan, and Expedition 364 Science Party, Quantifying the Release of Climate-Active Gases by Large Meteorite Impacts With a Case Study of Chicxulub. Geophysical Research Letters, 44 (20):10,180-10,188, 2017. http://dx.doi.org/10.1002/2017GL074879
  4. Julia Brugger, Georg Feulner, and Stefan Petri, Baby, it’s cold outside: Climate model simulations of the effects of the asteroid impact at the end of the Cretaceous. Geophysical Research Letters, 44 (1):419-427, 2017. http://dx.doi.org/10.1002/2016GL072241
  5. Kunio Kaiho and Naga Oshima, Site of asteroid impact changed the history of life on Earth: the low probability of mass extinction. Scientific Reports, 7 (1):14855, 2017/11/09 2017. https://doi.org/10.1038/s41598-017-14199-x

 

PS.  Some great names for bands:

Chicxulub
The Chicxulub Event
We Are Children of Chicxulub
Thanks to Chicxulub
Brought to You By Chicxulub