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Rodent that was as big as a bull Trends Prof Yash
Pal
THIS UNIVERSE |
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The sixth extinction
THE news of environmental traumas assails us from every side — unseasonal storms, floods, fires, drought, melting ice caps, lost species of river dolphins and giant turtles, rising sea levels potentially displacing inhabitants of Arctic and Pacific islands and hundreds of thousands of people dying every year from air pollution. Last week brought more — new reports that Greenland’s glaciers may be melting away at an alarming rate. What’s going on? Are we experiencing one of those major shocks to life on earth that rocked the planet in the past? That’s just doomsaying, say those who insist that economic growth and human technological ingenuity will eventually solve our problems. But in fact, the scientific take on our current environmental mess is hardly so upbeat. More than a decade ago, many scientists claimed that humans were demonstrating a capacity to force a major global catastrophe that would lead to a traumatic shift in climate, an intolerable level of destruction of natural habitats, and an extinction event that could eliminate 30 to 50 per cent of all living species by the middle of the 21st century. Now those predictions are coming true. The evidence shows that species loss today is accelerating. We find ourselves uncomfortably privileged to be witnessing a mass extinction event as it’s taking place, in real time. The fossil record reveals some extraordinarily destructive events in the past, when species losses were huge, synchronous and global in scale. Paleontologists recognise at least five of these mass extinction events, the last of which occurred about 65 million years ago and wiped out all those big, charismatic dinosaurs (except their bird descendants) and at least 70 per cent of all other species. The primary suspect for this catastrophe is a six-mile-wide asteroid (a mile higher than Mount Everest) whose rear end was still sticking out of the atmosphere as its nose augered into the crust a number of miles off the shore of the present-day Yucatan Peninsula in Mexico. Earth’s atmosphere became a hell furnace, with super-broiler temperatures sufficient not only to kill exposed organisms, but also to incinerate virtually every forest on the planet. For several million years, a period 100 times greater than the entire known history of Homo sapiens, the planet’s destroyed ecosystems underwent a slow, laborious recovery. The earliest colonisers after the catastrophe were populous species that quickly adapted to degraded environments, the ancient analogues of rats, cockroaches and weeds. But many of the original species that occupied these ecosystems were gone and did not come back. They’ll never come back. The extinction of a species, whether in an incinerated 65-million-year-old reef or in a bleached modern-day reef of the Caribbean, is forever. Now we face the possibility of mass extinction event No. 6. No big killer asteroid is in sight. Volcanic eruptions and earthquakes are not of the scale to cause mass extinction. Michael Novacek, a paleontologist, is senior vice president and provost of the American Museum of Natural History. He is the author of “Terra: Our 100-Million-Year-Old Ecosystem — and the Threats That Now Put It at
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Rodent that was as big as a bull THE fossilised skull of a giant rodent that grew to the size of a bull has been discovered in South America, where it lived about four million years ago alongside sabre-toothed cats, huge flightless “terror” birds and giant ground sloths. Scientists have found the almost complete skull of the extinct rodent, which weighed about a ton and grew about 5 ft tall and about 9 ft long. Rodents, which include rats, mice and guinea pigs, are the most abundant group of living mammals. The latest discovery shows that they are also physically one of the most varied, ranging from a few grams — the size of a pygmy mouse — to about 1,000 kg, the weight of the extinct South American specimen. Scientists believe that the rodent may have lived on fruit and leaves, similar to the diet of its closest living relative, the pacarana, another South American rodent that grows to about 3 ft long and weighs about 13 kg. Both the extinct rodent and the living pacarana belong to the Dinomyidae family of mammals. The skull of Jospehoartigasia monesi, as the species has been named, is described in the “Proceedings of the Royal Society B” by Andres Rinderknecht of Uruguay’s National Museum of Natural History and Ernesto Blanco of the Institute of Physics in Montevideo. “This species with estimated body mass of nearly 1,000 kg is the largest yet I recorded. The skull sheds new light on the anatomy of the extinct giant rodents of the Dinomyidae, which are known mostly from isolated teeth and incomplete mandible remains,” the scientists said. Scientists believe giant rodents may have become extinct because they were too big to dig burrows and too slow to outrun
predators.
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Trends “It’s an odd universe we live in,” said Vanderbilt University astronomer Kelly Holley-Bockelmann. She presented her theory on rogue black holes at the American Astronomical Society’s meeting in Austin, Texas, earlier this week. It should be noted that she’s not worried and you shouldn’t be either. The odds of one of these black holes swallowing up earth or the sun or wreaking other havoc is somewhere around 1 in 10 quadrillion in any given year.
— Reuters
Darkest material on earth And the material is close to the long-sought ideal black, which could absorb all colors of light and reflect none.
— Reuters
Cloned animals safe to eat Consumer anxiety about cloning is serious enough that several major food companies, including the big dairy producer Dean Foods Co. and Smithfield Foods Inc., say they aren’t planning to sell products from cloned animals.
— AP
Butterflies use body clock An internal biological clock that enables the 24-hour cycle of night and day allows the monarch butterfly to calculate its direction of flight when migrating either north or south, depending on the time of the year, scientists have discovered. Monarch butterflies are famous for the journey they make each spring from their winter roosting sites in the mountain pine trees of Mexico to as far as the US-Canadian border and back again in autumn — an unparalleled migratory feat for such a small creature.
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THIS UNIVERSE
Why same charges repel and opposite charges attract? Please explain this on the basis of physics. You have asked a difficult question. Why should there be this two-ness in the properties of fundamental particles? I could just say that we have found it to be so. Nature is like that. We may also say that we happen to be because it is so. If it were not we would not have the universe we do. Atoms, molecules, whole of chemistry and biology we know won’t be there. This is the nature of the electromagnetic field that controls it all. Imagine if this field was like the gravitational field and all particles attracted all other particles. The very nature of that field would be different. Indeed we cannot even have a theory of photons without postulating the existence of electrons and positrons that on combining annihilate charge. In fact the theory of electron itself demanded that there exist a particle of equal and opposite charge. I do not know whether you can make more sense out of what I have said than I do. I hope so. How does the computer keep all the data in its memory/hard disk? The data is preserved in a digital format. The digits, 0 and 1 or yes and no, can code all information, be it text, numbers, pictures, or sound. This digital information is recorded the same or similar way as the recording in a cassette recorder. In a solid-state memory these digits are stored as states of electronic switches, open or closed. |
THE deeper astronomers gaze into the cosmos, the more they find it’s a bizarre and violent universe. The research findings from this week’s annual meeting of U.S. astronomers range from blue orphaned baby stars to menacing “rogue” black holes that roam our galaxy, devouring any planets unlucky enough to be within their limited reach.
U.S. researchers said on Tuesday they have made the darkest material on earth, a substance so black it absorbs more than 99.9 per cent of light. Made from tiny tubes of carbon standing on end, this material is almost 30 times darker than a carbon substance used by the U.S. National Institute of Standards and Technology as the current benchmark of blackness.
Just over a decade after scientists cloned the first animal, the last major barrier to selling meat and milk from clones has fallen: The U.S. government declared this food safe Tuesday. Now, will people buy it?
The spectacular migration of the monarch butterfly, which covers a 2000 miles round trip in a year, uses an inbuilt precision clock that enables the insect to use the sun as a compass, a study has found.