Gravitational waves

Has the LIGO observatory observed gravitational waves? Rumours have been rife that LIGO (Laser Interference Gravitational Wave observatory) has picked up the signature of gravitational waves   (ripples in space time) arising from a massive cosmic event, the collision of two black holes. Astronomers have been looking for confirmation of the rumoured LIGO events  in the form of an optical flash in three parts of the sky, in the constellation Dorado, as well as in the constellations Aries and Hydra. The last time the classic signature (a `chirp') was observed in the LIGO data was in 2010, but it was announced to be a false signal, fake data inserted to ensure that the analysis could, in fact detect a signal. The experiment has scheduled a press conference on 11th February, where they may confirm the observation, (or not!).  More tomorrow,  the entire physics world waits with bated breath. Hopefully, the LIGO spokespersons will not shout April Fool, in February!


 Update: February 12th:

They did find it. We had the unique experience of hearing the universe chirp, that too on our mobiles (the quality of the broadcast was absolutely wonderful!). Gabriela Gonzales provided the details. Two massive black holes of solar masses 36 and 29 coalesced to form an object of 62 times the solar mass. Their motion, which spiralled round each other, before the collapse (250  revolutions per second at half the speed of light) provided the chirp. This event occurred a billion light years ago, at a time when life on earth had barely progressed to multicellular organisms, at a location roughly in the direction of the Magellanic cloud. The observation was a triumph of state of the art experimental technique and technology, the mirrors of the interferometer moved through a distance of 4/1000ths of the diameter of the proton due to the effect of the wave. As far as the theory is concerned, the original prediction dates back to Einstein in 1916, and Taylor and Hulse had made an indirect observation of the gravitational waves which would have been obtained due to two neutron stars spiralling inwards coalescence. Taylor and Hulse got the Nobel for their discovery. So who is in line this time? The three originators of LIGO were Kip Thorne,  Rainer Weiss and Ronald Drever, and of course,  there are now younger collaborators. The Bicep2 team must be sad at having missed the first detection, although they may still get the first wave from the big bang. The result is also a vindication of big science. The National Science Foundation spent $1.1 billion over the LIGO detectors at  Livingston, Louisiana and Hanford, Washington over 40 years, including the recent upgrade to the Advanced LIGO lab, which finally bought the detectors to the stage where the recent detection became possible.  The result came almost immediately after the upgrade, last September, just after the calibration of the advanced LIGO system. The result is a collaboration between these two LIGO Labs and the Virgo observatory in Europe.  There are three more events in the pipeline, which are currently under analysis. Two more LIGO labs are proposed, one in Japan, and one in India, where they will hopefully find adequate funding support and ecological blessing from all concerned parties! These are exciting times to be in physics. These discoveries are invitations on the part of the discipline to join the excitement.

This blog post by Neelima Gupte and Sumathi Rao.

Postscript: The original paper has appeared in Physical Review letters yesterday. It's great to see a Chennai institute, Chennai Mathematical Institute, Chennai in the affiliation list of the authors.

 What did the blackbird say to the black holes?  `And a chirp to you, too'.

Update 16/06/16

A second gravitational wave event has been detected, again from the coalescence of two black holes, somewhat smaller than the ones which collided in the first event. This second event was a Christmas gift from the universe to us. The data analysis took six months, which is why the event was only announced last week. As for the details, one can't do better than quote  the succinct Physical Review Letters abstract, reproduced below. So here you are, error bars and all.

'We report the observation of a gravitational-wave signal produced by the coalescence of two stellar-mass black holes. The signal, GW151226, was observed by the twin detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO) on December 26, 2015 at 03:38:53 UTC. The signal was initially identified within 70 s by an online matched-filter search targeting binary coalescences. Subsequent off-line analyses recovered GW151226 with a network signal-to-noise ratio of 13 and a significance greater than 5σ. The signal persisted in the LIGO frequency band for approximately 1 s, increasing in frequency and amplitude over about 55 cycles from 35 to 450 Hz, and reached a peak gravitational strain of 3.4+0.7−0.9×10−22. The inferred source-frame initial black hole masses are 14.2+8.3−3.7M⊙ and 7.5+2.3−2.3M⊙, and the final black hole mass is 20.8+6.1−1.7M⊙. We find that at least one of the component black holes has spin greater than 0.2. This source is located at a luminosity distance of 440+180−190  Mpc corresponding to a redshift of 0.09+0.03−0.04. All uncertainties define a 90% credible interval. This second gravitational-wave observation provides improved constraints on stellar populations and on deviations from general relativity.'

A humongous Higgs?

Last week's blogs and websites have been atwitter with news of what could be a new Higgs boson. Both the ATLAS and CMS collaborations have seen `a bump in the data' at 750 GeV. Both collaborations have been seeing that proton-proton collisions that result in an unexpected number of di-photon pairs, pairs of photons which together carry away about 750 GeV of energy. This could be a new Higgslike boson, but 6 times more massive than the Higgs boson of the Standard model discovered in 2012. The statistics are nowhere near a level at which, anyone can claim an actual discovery, nor have the spokesmen of either collaboration done so. Atlas has discovered about 40 more pairs of photons, than what is predicted by the Standard model, and CMS has found just 10. However, it is intriguing that two independent experiments have found the photons at exactly identical energies. It could be a hulking Higgs after all! Of course, this could all vanish away into nothing. Watch this space for further updates.

Update: 05/08/16

Alas, it did vanish away into nothing, despite 500 theory papers. (The experimentalists were *not* guilty of overhyping the data). There was even a Game of Thrones citation contest on the this. Until
next time then, when we hope actual business will result.


Tailpiece: What did the HB say to the HHB ? You may be incredible, but I am Noble.

New Tailpiece: What did one photon say to another? I think all this was a bit much!


This blog post by Neelima Gupte and Sumathi Rao.

Bihar and Samose

Jab tak  samose mein hai aloo,

Jungle mein  hai bhaloo,

Bihar mein hai Laloo.

Well, Nitish Kumar, strictly speaking, but there is no denying the role of Laloo in the Mahagathbandhan's thumping  victory in the Bihar elections. This was one occasion on which the Mahagathbandhan got everything right, the electoral alliance, the caste politics, Nitish's governance, Laloo's grassroots base and the Congress' achievement in putting everyone together.

The BJP erred in not controlling the RSS demagoguery, aroused fear among Muslims, made ill timed remarks on the abolition of reservations, and missed the fact that the Modi magic had waned, at least at the state level. The results were there for all to see. All but one of the exit polls had indicated the trends clearly, although the one which predicted the thumping victory, attributed it in the wrong direction. The TV channels leaned in the same direction, until the actual numbers started kicking in.

So does this indicate that the Indian electorate has changed its mind? Its hard to say. The jantajanardan has voted in opposite directions in state and central polls, a countless number of times. On the other hand, the ruling dispensation has perhaps received warning that it should not lose its way into delusions of invincibility. Maybe that is a sufficient lesson, for the present.

This blog post is by Neelima Gupte and Sumathi Rao.

The cross roads of the world

Where does East meet West, Europe meet Asia, where do the great conquerors cross paths, where do the world's great religions clash and cross over? At Istanbul, of course, besides the beautiful blue Bosphorus. Identities merge and emerge, opinions clash and synthesise,  territories change and rechange hands, civilisations syncretise, resulting in the most glorious art, architecture and literature that the world has ever seen.  Here is a picture of the crossroads of the world, note the distances to Russian cities  and to Babylon. The actual ancient crossroads are the Milion monument, the stone structure on the right, which was the starting point of the great Roman road Via Egnetia, that lead to European cities, and the reference point to all distances on it.  The crossroads of the world now faces the influx of refugees from Syria, and as the Turkish premier pointed out, has been far more generous than most countries of Europe with its hospitality.

The city is full of mosques, and churches and palaces, minarets and steeples, Byzantine architecture overlaid with Ottoman flourishes. Practically nothing in the city has not changed hands, not once, but several times. The blue mosque is one of the most famous mosques in Istanbul. The Aya Sophia mosque  just opposite it is now a museum, and  has changed function many times.

The heart of the city is the Bosphorus, and the bridges across it, bridging Asia and Europe. The Bosphorus cruise and the suspension bridges across it, constitute the highlights of any Istanbul trip. Public transport in the city covers all bases, ferry, tram, bus and taxi.

Here is a not so common Istanbul experience. A trip to an island in the Bosphorus, a lovely place with 150 year old houses, and a charming neighbourhood feel. Lucky are the friends who live there, who shared their gracious household with us. No motorized transport allowed here. If you won't walk, take a horse drawn carriage.

As always it was too short a trip. So here's to hoping we visit again to catch the many wonders we missed, and to meet again the warm citizens of the city who spent enormous time and trouble shepherding around confused foreigners.


This blog post is by Neelima Gupte and Sumathi Rao.

New Horizons

Nasa's spacecraft, New horizons is flying by Pluto today, its point of closest approach scheduled for this morning EST (late afternoon for us). The mission is expected to yield new insights into the last known world, the icy dwarf planet, which had its status demoted from a planet a few  years ago, much to the chagrin of those who always thought it was a planet (viz. us!). Since this is the first fly by Pluto, the planetary scientists are licking their lips, waiting for data of kinds never seen before. Every first fly by other planets like Mars, Saturn and Jupiter has revealed unexpected features. Pluto is about to reveal its secrets. New horizons are about to be seen in planetary astronomy. Do stand by.

Photo: NASA, Pluto and Charon, July 12, 2015. Picture taken by the New Horizon spacecraft.

 16/07/2015

New horizons emerged safely from the fly by and communications blackout, and is beaming stunning pictures from the fly by. Here is an icy mountain.

 This mountain is as high as the Rockies, and is fairly young, as seen by the lack of craters. This evidence of recent geological activity in the icy planet will provoke much speculation, and new geological theories. Meanwhile CERN found the pentaquark yesterday, so quantum mechanical scales are competing with astronomical scales in new discoveries. This is truly an exciting time to be a physicist. Let's see what both scales throw up next.

 17/07/2015

More goodies from the New Horizons bag. A mountain in a moat on Charon. Here is the picture.

The heart shaped feature seen in the most popular Pluto picture are really icy plains which look like this:

By the way, the processor on New Horizons is a reprogrammed PlayStation chip. It shows anything that can play video games, can fly across the Solar System and and send back the most amazing data and pictures. Was it worthwhile having a nine year mission for a three minute flyby? You bet it was!
Just look above.


This blog post is by Neelima Gupte and Sumathi Rao.

The Chennai Metro

This is a highly local post, but why must we always be global?  The Chennai Metro was inaugurated yesterday, with minimal fanfare via video-conferencing,  by Tamil Nadu CM Jayalalitha, and with great enthusiasm by Tamil Nadu's (or more accurately) Chennai's general public. The first line from Alanthur to Koyambedu was crammed with everyone from children to housewives to office-goers to policemen, all in great spirits and busy clicking selfies, to mark the occasion. The first metro was driven by a young lady,  A. Preethi, who changed jobs to fulfil her dream of becoming a loco driver, and whose mother burst into tears at the happiness of the occasion.

Here you see the train, festooned with jasmine, as befits a smartly dressed lady from our city, and here you see where she is dressed up to go.  Alas, it's nowhere near us as yet. We will have to make do with the MRTS (that is the mustard line in the map), which was equally thrilling when it came, and still causes squeals of excitement when it whizzes past our balcony, albeit in the distance.  Finally,  fast cars, aeroplanes, rockets and the Mangalyaan not withstanding, there is nothing like a train!

This blog post by Neelima Gupte and Sumathi Rao.

Land of kings 3

Here is instalment three of the Land of Kings series. This time its Udaipur, Kumbhalgarh, Ranakpur and Mount Abu. Of these Udaipur needs no introduction. It's the most scenic location in Rajasthan, and as such, has featured in everything from movies to TV. Its most iconic son, Rana Pratap, is honoured in legend and song. The city palace at Udaipur has everything a palace should ever have, from the Sun symbol of the Sisodias, to grand rooms, beautiful murals, shady courtyards, and of course a sheesh mahal, apart from some of the

the most beautiful paintings that can be seen in Rajasthan. The lake palace, is a distant mirage in the lake, alas; only accessible to the well-heeled.  Haldi ghati, with its famous battle, and tales of valour, loyalty and betrayal, is also far from the city, but Rana Pratap and his loyal horse Chetak stand guardian over the city.

On next to Kumbhalgarh, made by Rana  Kumbha and used by Udai Singh and Rana Pratap during their long drawn battles with the Mughals. The fort  wall is second only to the great wall of China in length. The history of the fort consists  of happy occasions, such as the birth of Rana Pratap in 1540 as well as unhappy ones such as the murder of Rana Kumbha by his own traitorous son Ude in 1468.  The fort owes its existence to the sacrifice of a sage who offered himself as sacrifice so that the fort could be built. The gate of the fort was made where his head fell, and the walls where his body did.  A temple to him was made inside the fort walls. The fort is almost impregnable, and only fell in battle once. A spectacular view of the Aravallis can be seen from the topmost ramparts. The sound and light show at night is full of these wonderful stories, far better than the show at Amer, those who fought the Mughals make for the good stories, not the ones who fought for them! We had the good fortune of seeing it on a full moon night, when the air is full of the whisperings of those who lived here before.

The last leg of the journey were the Jain temples of Ranakpur and Mount Abu. The marble carving of the temples is literally lace in stone. No pictures, alas, photography being firmly prohibited. The Jain temples all over, over 300 in Kumbhalgarh, a huge number in Chittorgarh, reminds one that the history of Jainism in  the region predates both Rajputs and Mughals, and goes back to the 11th century. 

So we returned from the land of kings once again. No, no, this is not the last edition of the LOK. The golden fortress beckons still.

This blog post is by Neelima Gupte and Sumathi Rao.