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10 | Science Reporter | May 2019
SPECTRUMStudy Disproves Hawking, Shows Tiny Black Holes May Not Account for Dark Matter
AN international research team including Dr Surhud More and Dr Anupreeta More from Inter-University Centre for Astronomy and Astrophysics (IUCAA),
Pune, has ruled out the possibility of primordial black holes being a major constituent of Dark matter. This finding disproves a theoretical claim of Prof Stephen Hawking.
In the solar system, Mercury, the planet closest to the Sun, takes just 88 days to make one revolution around the sun, while Neptune, the farthest one, takes 165 years to make one round. Laws of gravity expect us to see stars closer to the centre of galaxies rotating faster than the stars on the edge. However, in most galaxies, the stars closer to the centre and the stars at the edge of the galaxies take almost the same time to make one revolution. This implied that something invisible and enveloping the galaxies was giving an extra push to the outer stars, speeding them up. This entity has remained as one of the central unresolved puzzles in cosmology since 1930s. It is, no wonder, named `Dark Matter’.
The material is considered to be a ‘matter’ since it appears to have gravitational attraction and it is ‘dark’ because it does not seem to interact with light (or for that matter any part of the electromagnetic spectrum). Detailed surveys of the cosmos indicate that almost 85% of the total mass of the Universe is composed of dark matter. Thus, stars, galaxies, and atoms that we see all around are just the tip of the iceberg and the elusive dark matter makes up the bulk of the Universe.
Cosmologists have come up with various hypothesis and theories to explain the dark matter. Some postulate it to be composed of neutrinos, which are particles that have no charge but have tiny mass and, therefore, do not interact with electromagnetic spectrum, but are gravitationally interacting. Some others have postulated they may be some new kind of elementary particles – ‘Weakly Interacting Massive Particles (WIMPs)’, or ‘Gravitationally Interacting Massive Particles’ (GIMPs), which are yet to be detected.
When the big bang hypothesis was proposed, two Soviet physicists, Yakov Borisovich Zel’dovich and Igor Dmitriyevich Novikov, showed that at the initial instant of the big bang, the
USUALLY we think that the cause of dengue is limited to a mosquito bite but the real villain is a virus transmitted by the vector dengue mosquito. Can we prevent the
transmission of these viruses from the mosquito bite? Well, the answer is the bacterium Wolbachia pipientis.
Wolbachia is a naturally occurring parasitic bacterium in many insects (hosts). It is majorly found in the gut and reproductive parts of the mosquito and reduces the ability of a mosquito to transmit viral diseases like Dengue and Chikungunya; thereby preventing the virus transmission by the mosquito.
The novel biocontrol approach is safe, cost-effective, eco-friendly and most importantly sustainable. A company in Singapore has created a device that helps in infecting mosquito larvae with Wolbachia in just three minutes. The company has also collaborated with the government to devise a larvae counter, pupae counter and a releasing device for Wolbachia-infected mosquito.
Have a Safe Mosquito Bite!
May 2019 | Science Reporter | 11
densities would have been very high at many points, resulting in the formation of small black holes. They were named ‘primordial black holes’. Stephen Hawking investigated them in 1971. He computed that the mass of the primordial black holes could range from as low as one-hundredth of a milligram to as high as more than the mass of thousand Suns.
Black holes are not radiant and will not be visible through any telescope. However, as first suggested by Albert Einstein, if by chance, a tiny primordial black hole eclipses a distant star, light rays of the star will bend around the black hole due to gravitational effect, resulting in the star appearing to be brighter than it originally is for a short while. Called ‘gravitational lensing’, this rare phenomenon can occur only when the star, the black hole and the observer on the Earth are aligned in a straight line.
The research team, which was led by Masahiro Takada, Hiroko Niikura and Naoki Yasuda from Kavli Institute for the Physics and Mathematics of the Universe used the Hyper Suprime-Cam on the Japanese Subaru Telescope located in
Hawaii to look for any tell-tale evidence of primordial black holes between Earth and Andromeda galaxy using gravitational lensing technique.
The research team observed the entire disk of the Andromeda galaxy consisting of lakhs of stars. The chance of some primordial black holes, if they do exist in sufficient numbers, eclipsing any of these stars becomes significant.
“The investigation is delicate and tricky. The eclipsed star may brighten up for a period of a few minutes or a few hours due to gravitational lensing, requiring the team to take multiple images to catch the flicker, if any,” says Dr Anupreeta More.
For a whole night, the research team took 190 consecutive images of the Andromeda galaxy. “If the Universe is filled with invisible teeny weeny primordial black holes, with masses lighter than the moon, as postulated by Stephen Hawking, then we should have seen at least 1,000 gravitational lensing events. We saw at most one such candidate event, if not none. This implies Stephen Hawking’s theory that such black holes make up all of dark matter is wrong,” says Dr Anupreeta.
“Previous studies had already ruled out the existence of large numbers of primordial black holes that could range in size from the mass of the Moon to about 10 solar masses. The present study rules out the presence of primordial black holes with masses comparable to the moon and sizes of about 0.1 millimeter too. This implies that at best the lunar mass primordial black holes can contribute 0.1 per cent of all dark matter mass,” says Dr Surhud More, another member of the research team.
A report on the work has been published in Nature Astronomy.
Dr T.V. Venkateswaran, India Science Wire
St. Augustine Anastasia Mosquito Control District has even organised a field trial where it released around 1,20,000 mosquitoes per week in a twenty-acre land. Another trial conducted by Monash University aimed at replacing the indigenous dengue mosquito population with the Wolbachia infected mosquito was carried out in Queensland.
India has also adopted this approach and is the sixth country in the world to participate in the Eliminate Dengue Program (EDP). EDP and Monash University have collaborated with the Indian Council for Medical Research (ICMR) for tack ling Dengue and Chikungunya.
Contributed by Srinivas Patil, Amity Institute of Microbial Technology, E3 Block, 4th floor, Amity University, Sector-125, Noida (UP). E-mail: [email protected]
Orinno Technology co-found-er David Du with the larvae counter (Photo: Courtesy Dr David Du)
12 | Science Reporter | May 2019
Androgenesis: An Optimistic Breakthrough for Pharmaceutical Industries
PLANT Tissue Culture (PTC) plays an important role in the manipulation of plants for enhanced agronomic performance. There is a large demand for disease-
free plants of superior quality in ornamental, horticultural, floricultural and agroforestry sectors, which form the core
sectors of agriculture. Haploidy (having a single set of unpaired chromosomes)
development via PTC is often a good way of developing inbred homozygous line (having a set of the identical paired chromosome; Double Haploid). Such improvement is possible by culturing anthers and pollen grains (paternal characters) of flowers in the laboratory; this phenomenon is called Androgenesis. As compared to conventional plant breeding, androgenesis reduces the time of plant improvement by almost 8-10 years. This technique was first reported by Indian researchers Guha and Maheshwari (1964) at the University of Delhi.
Research conducted at IIT, Guwahati (2011) on the plant Margosa i.e. Azadirachta indica A. Juss. has also increased production of phytochemical azadirachtin in the plants having
Lithophanes — 3D Print Your Sweet MemoriesLithophanes are etched pieces of artwork, especially pictures, on porcelain which comes to life when suitable backlight is provided. The word Lithophane originated from the Greek word ‘Lithos’ meaning ‘rock’ and ‘Phanein’ meaning ‘to appear’. If constructed properly, the image appears out of nowhere from a solid plate and hence the name.
Although lithophanes date back to the 18th century Europe or even earlier in China, according to some historians, the advent of 3D printing technology has once again brought them back to life.
3D printed Lithophanes can be used as gift items, wall mounts, night lamp shades, lantern covers or customised home-decors. The advantages of 3D printed Lithophanes are that they are quite budget friendly compared to porcelain ones, stay undamaged for a longer period of time than conventional photos and also look cool!
Now, if you are planning to print them yourself, you should keep a few things in mind. First, the picture you are choosing must be of HD resolution and have contrasting features. Second,
lithophanes are best printed vertically rather than laying on the build plate. Also, set the minimum layer height supported by your printer with print speed around 30mm/sec. Finally, use a light and bright coloured filament (not transparent) for best results.
Given here is a test print of a photo of Nikola Tesla. It’s not quite a perfect specimen due to the small size and the filament colour (unfortunately I have blue filament only at present). But you can see how it works.
But how to get them done if you don’t have a 3D printer? Don’t worry. There are certain online stores and manufacturers like Amazon and Soch3D.com who will print your customised lithophanes saving you labour for a reasonable cost.
Contributed by Debanjan Bakshi, MTech Electronics and Instrumentation Engineering, Gopinath Pal Lane, Palpara, Behind Morton Dairy, Chandannagar, Dist-Hooghly-712136, West Bengal. Email: [email protected]. Website: https://visioneducationindia.blogspot.com
With backlight (left) and without backlight (right)
Photo courtesy Pinshape.com
An ideal print will look something like this
May 2019 | Science Reporter | 13
THE noisy crackers burst during festivities like Diwali, New Year eve or wedding celebrations not only cause environmental disturbances and health problems for
humans but also terribly upset the canines too. They often run away from their homes, dogs may fall ill, some pets may lose bladder and bowel control or experience temporary diarrhoea.
A study conducted by the University of Bristol’s School of Veterinary Sciences found fireworks to be the most common trigger for fearful behaviour in dogs including trembling, shaking, hiding, seeking comfort, destruction, urination and salivation. Pets are also exposed to toxic fumes and pollutants released by fireworks which may severely affect their respiratory system.
Recently, the car company Ford has built a sound-proof doghouse that can provide relief to pets. The stylish kennel has an artificial door that lets the pet get in when it needs to, and also helps reduce the noise from the fireworks. There is also ample insulation in the kennel to help deaden the noise of firecrackers which can be as high as 120 decibels – considered to be the threshold for humans to experience pain. One can easily understand the distress the pet, whose ears are roughly four times more sensitive than human ears, has to experience.
A Sound-Proof Kennel Built by Ford can Pacify Pets
For building this kennel, Ford has used sound-cancellation technology that it uses in its cars. This technology is also used in headphones developed for plane and helicopter pilots to remove the monotonous drone of engines, especially on long flights.
According to research conducted by Ford, around 45% of dogs show signs of fear during loud noises due to the bursting of firecrackers and some dogs even flee from their homes in search of a secure spot.
It goes without saying that we should be sensitive enough towards our pets and other animals and care for them so that they are not subjected to unnecessary fear, stress or anxiety during festive times.
Contributed by Dr P.K. Mukherjee, 43, Deshbandhu Society, 15, I.P. Extension, Patparganj, Delhi-110092. Email: [email protected]
doubled paternal characters. The prerequisite for getting such an enhanced production of chemicals is the mass production of plants through this technique. Likewise, a research article published in the journal Planta Medica (1988) on Datura plant had reported variation in alkaloid contents in naturally occurring plants and the double haploid plant regenerated in vitro.
The curative effects of these plants can be credited to various phytochemicals such as alkaloids, sterols, tannins, phenolic acids, saponins, stilbenes, lignans, flavonoids, and terpenoids. Such compounds are biological assets for their activities, such as stimulation of the immune system, antimicrobial, modulation of detoxification enzymes, antioxidant, modulation of hormone
metabolism and anticancer property, and a decrease of platelet aggregation.
Pharmaceutical companies are facing a tough time in procuring medicinal plant materials for manufacturing alternative medicines as several medicinal plants are in short supply.
Herb demand is increasing because of the amplified interest of consumers in natural products as they are considered safer than synthetic drugs. According to the WHO, about 80% populations of African
and Asian countries are still dependent on traditional herbal medicines for their primary health care necessities. In general, international traffic in medicinal plants and herbal products was approximately US$ 60 billion in 2010 and is about to reach US$ 5 trillion by 2050.
Therefore, if the androgenesis technique is used successfully demand and supply of pharmaceutically important products of plant origin can be easily met.
Contributed by Mr Vivek R. Narkhedkar, Senior Research Fellow, Sant Gadge Baba Amravati University, Amravati (M.S.)-444602. Email: [email protected] Jaykiran A. Tidke, Professor and Head, Department of Botany, Sant Gadge Baba Amravati University, Amravati (M.S.)-444602
Prototype of a sound-proof kennel built by the car company Ford
Androgenesis in Catharanthus roseus (L.) G. Don. (Periwinkle)
