What it is : Physicists finally have a precise explanation how charged particles from the Sun causes the auroras above Earth’s northern latitudes.
Earth has a magnetic field that extends a long way into the sky. Above 1,000 km, lot of charged particles get trapped in this field. The field's imaginary field lines are shaped like a giant doughnut surrounding Earth, connected at the poles.
Many of these charged particles come from the Sun, released in events like solar flares. When they occur, curtains of light appear in the skies over Earth’s northern latitudes. These ‘curtains’ are called the aurora borealis. Until now, scientists didn’t know how exactly the particles caused auroras.
Now they do. The Sun also emits strong waves of energy called the solar wind. It stretches and compresses Earth’s magnetic field lines. Mostly, the field lines are compressed in front of Earth (on the side facing the Sun), and stretched like a tail behind (on the side facing away). When the solar wind breaks the field lines in front, they can reconnect at the back.
This reconnection event sends a wave of energy blowing through space. When it reaches Earth, it causes the aurora borealis.
Why it matters : When you go for a picnic, you check to make sure the weather’s OK. Similarly, knowing how the solar wind affects Earth is important to know what kind of protection satellites should have and where they can be positioned.
>Biological clocks defy circadian rhythms
What it is : Different studies have found that two marine invertebrates have more than one body clock, both working independently using different mechanisms.
Circadian clocks are found in every kingdom of life from fungi to humans. This allows various biological cycles to function according to whether it is day or night.
The speckled sea louse has swimming patterns that change with (every 12.4 hours). Scientists found out that that is enabled by another body clock called a circatidal clock which functions independently of the circadian one.
Another sea creature, the bristle worm, spawns at the same time every 30-day lunar cycle (the waxing and waning of the moon). It was discovered that the worm, too, has a non-circadian clock just like the sea louse -- a circalunar clock.
Both these discoveries were made by disrupting the creatures’ circadian clocks. This was done either by exposing them continuously to sunlight or by deactivating a key timing gene.
Why it matters : So far, our understanding of non-circadian rhythms has been hampered by not having access to organisms with experimentable distinct rhythms. Once scientists expose the underlying mechanisms of body clocks, it can be used to understand several aspects of human and animal behaviour. It may be that humans too have multiple clocks whose desynchronisation could lead to disease.
>Scientists create DNA barcodes
What it is : A team of researchers claim that they have developed a technique by which any product can be tagged with synthesized DNA and then subsequently read as a means of identification.
Scientists at the University of Aveiro, Portugal, believe that they can create and replicate a certain type of ‘molecular tag’ or ‘molecular barcoded labels’ in large quantities.
Each tag or label, depending on what it is used for, is made up of a cocktail of chimerical molecules of deoxyribonucleic acid (DNA).
These tags, which are non-toxic, can then be applied to a number of products—where they stay attached and can be easily read using low-cost portable equipment.
Why it matters : A unique property of these DNA barcodes is that they can simply be read like regular barcodes; no DNA-sequencing devices are required. These will have immense use in combating the counterfeiting of products, as the tags can be used as a method of verifying authenticity. According to the research team, the tags can even be combined with ink to verify someone’s signature.
>Transformer stars discovered with X-rays and radio waves
What it is : Scientists have discovered a strange pulsar that emits both X-rays and radio waves, contrary to prevailing understanding.
When a star heavier than our Sun by 8-50 times runs out of hydrogen, it blows away its outermost gases and collapses into its core, becoming an extremely dense rotating object called a neutron star. Neutron stars are known to emit either X-rays or radio waves, and these are emitted in focused beams. So, as the neutron star rotates, these beams periodically point toward Earth, giving us the impression that the neutron star is pulsating. Hence, they are also called pulsars.
Last week, NASA scientists announced that they’d discovered a pulsar that was emitting both X-rays and radio waves, switching between the two modes within milliseconds.
Probing further using the Swift space telescope, they found that the pulsar was switching modes because it was swallowing gas from a nearby star. As the amount of the gas rose and fell, so also did the radiation from the neutron star as it compressed different amounts.
Why it matters : The finding is important because such a ‘millisecond’ pulsar provides the first clues about why some pulsars generate X-rays and others, radio waves. Studying this transitional body can simplify, shorten and make cheaper the process of distinguishing between different pulsars in the night sky.
>Ancient soils provide early whiff of oxygen
What it is : A team of scientists claim that atmospheric oxygen on Earth may have appeared almost 700 million years earlier than thought.
It had, until now, been pretty much established that this pumping of oxygen into the atmosphere happened during an event called the Great Oxidation Event (GOE) which was when photosynthetic cyanobacteria really flourished in the vast shallow-water shelf environments created by continental rearrangement.
Now, scientists claim to have proof that there were significant levels of oxygen in the atmosphere at least 600 million years before the GOE. They proved this by studying the levels of the chromium-53 isotope in 2.9-billion-year-old soil.
The solubility of this isotope in water increases with amount of oxygen. So soils that have been oxygenised over time can be expected to be depleted of chromium-53 as rainwater would wash it away. Sea sediments, consequently, would be rich in this washed away chromium-53.
This is exactly what the scientists observed and led them to make their estimations.
Why it matters : This study, once confirmed, will indicate that photosynthesis and other complex metabolisms in lifeforms may have evolved a lot faster than we expect them to, thereby debunking an existing theory in evolution. Also, now that the efficiency of the chromium-53 technique has been proved, we can detect even smaller levels of oxygen in ancient Earth.
Compiled by Vasudevan Mukunth, Nandita Jayaraj & Anuj Srivas
