What would be most dangerous, if an asteroid hits the Earth?

Courtesy: American Geophysical Union release

If an asteroid struck Earth, which of its effects—scorching heat, flying debris, towering tsunamis—would claim the most lives? A new study, published in Geophysical Research Letters and described as the first to look at all seven impacts of dangerous asteroids,  has the answer: violent winds and shock waves are the most dangerous effects produced by Earth-impacting asteroids. Shock waves arise from a spike in atmospheric pressure and can rupture internal organs, while wind blasts carry enough power to hurl human bodies and flatten forests.

The study explored seven effects associated with asteroid impacts—heat, pressure shock waves, flying debris, tsunamis, wind blasts, seismic shaking and cratering—and estimated their lethality for varying sizes. The researchers then ranked the effects from most to least deadly, or how many lives were lost to each effect. According to the scientists, this is the first study that looks at all seven impact effects generated by hazardous asteroids and estimates which are, in terms of human loss, most severe.

Overall, wind blasts and shock waves were likely to claim the most casualties, an AGU release citing the study says. In experimental scenarios, these two effects accounted for more than 60% of lives lost. Shock waves arise from a spike in atmospheric pressure and can rupture internal organs, while wind blasts carry enough power to hurl human bodies and flatten forests.

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Thankfully, it does not happen too often. The lead scientist Clemens Rumph, a Marie Curie Senior Research Assistant within Engineering and the Environment at the University of Southampton, also reported in another paper accepted for publication in Meteoritics and Planetary Science on 04 February 2017 that “an asteroid impact is a low probability event with potentially devastating consequences.”

And that “the Asteroid Risk Mitigation Optimization and Research (ARMOR) software tool calculates whether a colliding asteroid experiences an airburst or surface impact and calculates effect severity as well as reach on the global map. To calculate the consequences of an impact in terms of loss of human life, new vulnerability models are derived that connect the severity of seven impact effects (strong winds, overpressure shockwave, thermal radiation, seismic shaking, ejecta deposition, cratering and tsunamis) with lethality to human populations. With the new vulnerability models ARMOR estimates casualties of an impact under consideration of the local population and geography. The presented algorithms and models are employed in two case studies to estimate total casualties as well as the damage contribution of each impact effect. The case studies highlight that aerothermal effects are most harmful except for deep water impacts, where tsunamis are the dominant hazard. Continental shelves serve a protective function against the tsunami hazard caused by impactors on the shelf. Furthermore, the calculation of impact consequences facilitates asteroid risk estimation to better characterize a given threat and the concept of risk as well as its applicability to the asteroid impact scenario are presented. “

Gravitational Wave kicks out monster black hole kicked out of distant galaxy core

Courtesy:  AAS release and HubbleSite News:

Astronomers have uncovered a supermassive black hole that has been propelled out of the center of a distant galaxy by what could be the awesome power of gravitational waves.

Weighing more than 1 billion Suns, the rogue black hole is the most massive black hole ever detected to have been kicked out of its central home, says a release from teh American Astronomical Society.

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Enter a captionHubble catches runaway black hole — the ost massive detected from its core — Credit: Hubblesite.org

Researchers estimate that it took the equivalent energy of 100 million supernovas exploding simultaneously to jettison the black hole. The most plausible explanation for this propulsive energy is that the monster object was given a kick by gravitational waves unleashed by the merger of two hefty black holes at the center of the host galaxy.

First predicted by Albert Einstein, gravitational waves are ripples in space that are created when two massive objects collide. The ripples are similar to the concentric circles produced when a hefty rock is thrown into a pond. Last year, the Laser Interferometer Gravitational-Wave Observatory (LIGO) helped astronomers prove that gravitational waves exist by detecting them emanating from the union of two stellar-mass black holes, which are several times more massive than the Sun.

Hubble’s observations of the wayward black hole surprised the research team. “When I first saw this, I thought we were seeing something very peculiar,” said team leader Marco Chiaberge of the Space Telescope Science Institute (STScI) and Johns Hopkins University, in Baltimore, Maryland. “When we combined observations from Hubble, the Chandra X-ray Observatory, and the Sloan Digital Sky Survey, it all pointed towards the same scenario. The amount of data we collected, from X-rays to ultraviolet to near-infrared light, is definitely larger than for any of the other candidate rogue black holes.”

Chiaberge’s paper will appear on March 30 in Astronomy & Astrophysics.

Hubble images taken in visible and near-infrared light provided the first clue that the galaxy was unusual. The images revealed a bright quasar, the energetic signature of a black hole, residing far from the galactic core. Black holes cannot be observed directly, but they are the energy source at the heart of quasars — intense, compact gushers of radiation that can outshine an entire galaxy. The quasar, named 3C 186, and its host galaxy reside 8 billion light-years away in a galaxy cluster. The team discovered the galaxy’s peculiar features while conducting a Hubble survey of distant galaxies unleashing powerful blasts of radiation in the throes of galaxy mergers.

The team calculated the black hole’s distance from the core by comparing the distribution of starlight in the host galaxy with that of a normal elliptical galaxy from a computer model. The black hole had traveled more than 35,000 light-years from the center, which is more than the distance between the Sun and the center of the Milky Way.
Read more at Hubblesite News

EXPERIMENTS SHOW TITAN LAKES MAY FIZZ WITH NITROGEN

From AAS Press and JPL :

A recent NASA-funded study has shown how the hydrocarbon lakes and seas of Saturn’s moon Titan might occasionally erupt with dramatic patches of bubbles.

For the study, researchers at NASA’s Jet Propulsion Laboratory in Pasadena, California, simulated the frigid surface conditions on Titan, finding that significant amounts of nitrogen can be dissolved in the extremely cold liquid methane that rains from the skies and collects in rivers, lakes and seas. They demonstrated that slight changes in temperature, air pressure or composition can cause the nitrogen to rapidly separate out of solution, like the fizz that results when opening a bottle of carbonated soda.

JPL Titan

CREDIT: NASA/JPL-Caltech/Space Science Institute

NASA’s Cassini spacecraft has found that the composition of Titan’s lakes and seas varies from place to place, with some reservoirs being richer in ethane than methane. “Our experiments showed that when methane-rich liquids mix with ethane-rich ones — for example from a heavy rain, or when runoff from a methane river mixes into an ethane-rich lake — the nitrogen is less able to stay in solution,” said Michael Malaska of JPL, who led the study.

Here’s a video courtesy JPL and read more at https://www.jpl.nasa.gov/news/news.php?release=2017-071

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Festival of Innovation — And Why Minds on the Margins are Not Marginal Minds

As the Festival of Innovation concluded in Delhi in March, its time to spare a thought for the countless small-scale rural innovations that escape the science and technology elite in India. And for Indian Institute of Management (IIM), Ahmedabad’ Professor Anil Gupta‘s tireless efforts to bring them recognition, through his Honey Bee Network and Society for Research and Initiatives for Sustainable Technologies and Institutions (SRISTI), and later the Grassroots Innovation Augmentation Network and National Foundation of India.

8th Annual Responsible Leadership Summit

Prof Anil Gupta Credit: IIM, Ahmedabad

This year, eight grassroots innovators from Kashmir won the national awards for their innovations. So did a musician from Nagland, Moa Subong, who is the backbone of the band Abiogenesis, for his innovative contribution towards traditional music. And the the Khasi and Jaintia communities for creating the living root bridges that serve as a communication network to remote villages.

Living root bridge

Living root bridge in northeastern India: credit: Anselmrogers, Wikipedia

I had a chance to travel to some of the most interior areas of Gujarat to see some of the innovations and meet the unsung innovators. And so, was only too happy to read Prof Gupta’s latest book: Grassroots Innovation – Minds on the Margin are not Marginal Minds. 

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Prof Gupta asks some uncomfortable questions. For example, Do innnovatons have to be mass-produced?

“Frugal solutions are not always seductive for scientists and policy makers and extension workers,” he writes, “perhaps these are not reassuring ideas for many because of their inherent democratic nature and ease of use without expert help. Lack of institutional support thus comes in the way of diffusion of such low-cost, easy-to-use innovations amongst those who need these most but may not have discovered them themselves.”

My  review in the Wire:

 

 

India’s grand plan to interlink rivers and create world’s longest

My report in New Scientist: Engineering projects don’t come any bigger than this. If India’s prime minister, Narendra Modi, gets his way, work could soon begin on a project to link large rivers in the Himalayas and Deccan Peninsula via 30 mega-canals and 3000 dams.

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Indian plans to link 14 Himalayan and 16 Peninsular rivers: Photo Credit Rupak De Chowdhuri/Reuters via New Scientist

When the work is finished the water network will be twice the length of the Nile, the world longest river, and it will be able to divert water from flood-prone areas to those vulnerable to drought.

But geologists and ecologists in India question the science behind the Inter Linking of Rivers (ILR) scheme. If it goes ahead it might lead to ecological disasters and coastal erosion that would threaten livelihoods and endanger wildlife.

Water network

Versions of the ILR scheme date back more than 60 years to the days of British rule in India. In its latest incarnation the plan is to link 14 rivers in north India and 16 in the western, central and southern parts of the country, creating a water network some 12,500 kilometres long. The idea is to reduce droughts and floods and create 35 million hectares of arable land in the process, as well as the means to generate 34,000 megawatts of hydropower.

This project is backed by Narendra Modi, who became the country’s prime minister in 2014. Since then India’s National Water Development Agency has completed detailed project reports for three key initial river links – the pilot link between Ken and Betwa rivers in northern and central India; Daman Ganga and Pinjal rivers in western India; and Par and Tapti rivers in western and central India. A feasibility report of a fourth link between three Himalayan rivers – Manas, Teesta and Ganges – is in the final stages of preparation.

But many researchers question the science behind the scheme. They say there isn’t a simple division between river basins that carry too little and too much water – and that climate change has triggered changes in rainfall patterns with unpredictable knock-on effects on water flow.

They argue that it would be unwise to set in stone a vast new canal network at a time of dramatic environmental change.

Read the full report in New Scientist :