Monday, June 26, 2017

Two big science stories

There were two big science stories last month, of vastly differing natures.

Our knowledge of human evolution took a giant leap backwards this fortnight. The oldest known remains of the species homo sapiens have been found in Morocco.  The fossils have been dated to be about 3,00,000 years old. The oldest specimens found before this, were about 1,95,000 years old, which means that the current discovery pushes back the origin of our species by about a 100,000 years. The geographic locations of the fossils, the Jebel Irhoud site in Morocco also indicates that humankind evolved at multiple locations in Africa, and there is no single cradle of humanity, as was thought earlier. The remains were dated by dating the artefacts, in this case, flint blades, found in the neighbourhood of the fossils. The fossils were clearly of the homo sapiens type, but were much, much older than anything found so far. The fossil evidence indicates that the specimens looked much like more modern members of the species, but their brain structure and shape resembled the long low shapes of other homonims, rather than the round shape of homo sapiens. The discovery will keep paleoanthropologists busy for a good long time.

The second story was of the type that makes us scientific types blasé these days. Two black holes  collided again, and the universe chirped again, yawn..... , exactly what we were squawking with excitement about, a scant 15 months ago! The Ligo detectors detected a third signal from the gravitational collapse of two massive spinning  black holes, of 19 and 31 solar masses, with spins which were not aligned,  to create a black hole of 49 solar masses, about 3 billion light years away. The surprisingly large frequency of such occurrences has led scientists to predict the birth of  a new area, namely, black hole astronomy.  The theoretical advance should come in the direction of identifying the reason for the frequent occurrence of black hole binaries, which then merge to set off the detected gravitational waves. In short more work for the practitioners of the current discipline.

To summarise, as always, the exciting discoveries need to be followed by huge amounts of painstaking analysis. Meanwhile, it is a pleasure to report that Indian scientists, including a colleague from IIT Madras, have been a part of the LIGO discovery. We look forward to more exciting results.

This blog post by Neelima Gupte and Sumathi Rao.

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