Breaking News from the Outer Space

The mysterious FRBs:

Astronomers are baffled by the FRBs (short for Fast Radio Bursts), persistent high energy signals from somewhere  far away, way  beyond our Galaxy. Detected almost a decade ago by Duncan Larimer of West Virginia University, initially  these were shrugged off as random noises. It was only last year  that researchers realised that at least one of them is a repeater with  signals  few thousands of a second long. Roughly 200 such signals have so far been received  from this repeater. And astronomers  estimate  the source could be  roughly 2.5 billion light years away.  It is still being debated whether the source is a faint dwarf galaxy or a a super powerful magentar, or an active galactic nuclei  or some thing else. Scientists   are treading vey cautiously  widening their horizons and peeping into other galaxies, assessing the  frequencies, checking for polarisation effects etc. Raw data will eventually do the talking, not speculation.  

SciFi  world writers and readers alike are  thrilled: they have been hoping to hear from E.T. ever since  he made friends with us.

  

Seven more Earths:

Humans  have an unexplainable fixation with number 7. Now Spitzer Space Telescope of NASA has   espied   seven earthlike planets revolving round a rather smaller sun. Because the Transiting Planets and Planetesimals Small Telescope located in Chile, did this spy work,  the new planetary system goes by the same name TRAPPIST-1. Michael Gillon, leader of Team TRAPPIST  says "The seven wonders of TRAPPIST-1 are the first Earth-size planets that have been found orbiting this kind of star".

Trappist-1 planetary system :An illustration Courtesy Hubble site 

The TRAPPIST-1 system seem to be a close knit family. So close that  a NASA report adds   "If a person was standing on one of the planet's surface, they could gaze up and potentially see geological features or clouds of neighbouring worlds, which would sometimes appear larger than the moon in Earth's sky. " Their orbital periods 1.51, 2.42,4.04, 6.06, 9.1 and 12.35 days respectively. And most important of all  Gillon et al state "their equilibrium temperatures are low enough to make possible the presence of liquid water on their surface !" But there is one hitch: the  short orbital periods imply the planets might be presenting  the same face to the Sun  like our Moon. 

Lay man is obsessed with just one question: will it support life as we know it?  As of now  it is difficult  to commit either way.  However   Ignas Stellan  at the Leiden Observatory, Leiden University  is absolutely certain about one thing -  the TRAPPIST  Sun has a very very long life span. It  will last for another 10 trillion years even after our own Sun has become nuclear ash,  because it is burning at an  extremely slow  rate. And in 10 trillion years anything can happen !

Ceres goes Organic 

NASA's DAWN spacecraft  has detected organic matter  on Ceres, the largest asteroid (or a  dwarf planet if you prefer) in the solar system. Dawn is equipped with  visible and Infrared spectrometers which can read out the chemical signatures of organic compounds.  Analysing  Dawn's data, the research team  suggests that the organics , linear carbon compounds, are native to Ceres.  It is presumed that the axial tilt facilitated accumulation of frozen water in the surface pockets  of Ceres.  The presence of clay and carbonate and now organics suggests chemical activity on Ceres  facilitated by a moist,  warm ambience.  

Chris Russell, principal investigator of the Dawn mission, based at the University of California, Los Angeles states that  "Dawn has revealed that Ceres is a diverse world that clearly had geological activity in its recent past.” 

Tailpiece

It has been more than a decade  since we downgraded and de-recognised Pluto.  However  there were/are many upset with that decision.  Efforts are on to bring Pluto and along with it many other cosmic bodies into the fold by redefining  a PLANET. The new definition runs like this:   

“ A planet is a substellar mass body that has never undergone nuclear fusion and that has sufficient self gravitation to assume a spheroidal shape adequately described by a triaxial ellipsoid regardless of its orbital parameters.” 

Or to put it bluntly as Nature Magazine: “Round objects in space that are smaller than stars.”

Aha do we see our dear Moon and all other moons of the solar system feeling elated at the possible upgradation?

Referencs:

1. A repeating fast radio burst Spitler L,.G et al Nature 531, 202-205 (2016)

2. A direct localization of a fast radio burst and its host Chatterjee, S et al Nature 541 58-61 (2017)

3. Seven temperate terrestrial planets around the nearby ultra cool dwarf star                 

    TRAPPIST-1: Gillon, M et al Nature 542,456-460 (2017)

4. Earth's seven sisters: Snellen, I.A.G. Nature 542, 421-423 (2017)

5  For more info on trappist1 

7. Dawn discovers evidence for organic material on Ceres

6. Pluto's Revenge: Nature Vol.542,23 Februar 2017 pp392

When communication goes viral

The new buzz word is viral; everything goes and grows viral these days-  Communication goes viral in an instant, thanks to the internet.   But how do the actual biological  viruses communicate , or do they communicate at all?  First report that they do  has appeared in the 26th January issue of Nature. 

But that was not the question a team scientists led by Prof. Rotem Sorek, Weizmann Institute asked. They were hoping to intercept bacterial communication. Bacteria are known to share information with descendants and close relatives  through chemical messengers.  The  process is referred to as quorum sensing. These  chemical messengers are small  peptide molecules whose presence and concentration level in the medium are signals  for the bacterial communities  to readjust or regulate their behaviour to maximise survival advantage.  The team set out to monitor the behaviour of Bacillus subtilis infected with various viruses.  Viruses  that infect   bacteria  are  called  bacteriophages  or simply phages. The word phage which has a Greek connection,  connotes gobbling up/consuming/annihilating. True, phages can gobble up their bacterial host, but there are times when they refrain from such an extreme step.  Here is the full story.  A  phage infecting a host  has two options :  either multiply  quickly and  kill of the host  or settle for a  live and let live policy temporarily, waiting for an opportune moment. The first one is called  lysis (or the lytic pathway)  and the second one is lysogeny (or  the Lysogenic Pathway).   Either way to counter the viral attack bacteria might put in place a defence strategy.  The Weizmann team   was  hoping to idenify and isolate messenger/s which  might provide clues  on the survival  strategies phage infected  bacteria might adopt.

The team  investigated  the  growth pattern of  Bacillus subtilis  infected with 4 different phages: phi29, phi105, rho14 and phi3T.  had hoped  to  spot a chemical messenger or messengers which facilitated bacterial communication.  But they were in for a surprise. Analysis of the bacterial broth infected with phi3T yielded   a small peptide molecule but it was  of viral origin.  Follow up studies established it to be a short peptide  used by the phi3T phage to communicate within its community, a kind of strategy signal to  successive generations.  Less of the peptide in the medium prompted the new generation  to get on a vigorous  lytic phase while   more of it in the medium proved to be  a warning signal   to get onto  dormant lysogenic phase. So in reality this was decision making process.  Excited, the  team gave an appropriate  name to the peptide-  arbitrium which in latin means decision.  The team also observed that during the initial stages of infection when bacteria to phage ratio is high, the concentration of arbitrium  in the medium is very low signalling  lytic phase.   During  the later stages of infection when almost all bacterial population is infected,  arbitrium  levels shoot up signalling new generations of the phages  to lie low  for the time being.    

References:

1.Communication between viruses guides lysis-lysogeny decisions:  Erez et al Nature vol541, pages 488-493,  January 26, 2017

2. Quorum sensing: cell to cell communication in bacteria: Waters & Bassler : Ann.Rev.Cell Dev.Biol  21:319-46 2005