By Akshay Asija
The year 2017 saw major developments in the realm of science and technology. The progress made this year has changed the perception of many scientists which will boost scientific research in the future. There were several such advancements throughout the year but five events stood out from the rest. These events had a deep impact on humans understanding of the universe that they inhabit. These also caused researchers to completely rethink some fundamental concepts.
Collision of two neutron stars
On August 17 this year, the Laser Interferometer Gravitational-Wave Observatory (LIGO) in the USA detected a gravitational wave (GW) signal that was generated due to the collision of two neutron stars. More specifically, as the two neutrons (dying) stars spiralled closer to each other and finally merged, a GW signal was emitted. It was the first signal of its kind that was captured by the LIGO. The GW signals that the LIGO had detected thus far had been generated due to merging black holes and had not been accompanied by an electromagnetic signal. Since this collision involved two neutron stars instead of black holes, it was followed by electromagnetic emissions of all kind that were recorded by 70 observatories around the world, and even in space. Many astronomers have likened the explosion caused by the collision to a firework show. Interestingly, Albert Einstein had predicted such gravitational wave producing collisions more than half a century ago.
This event, known as a kilonova, took place in a constellation called Hydra which is about 130 million light-years away from the Earth. The collision confirmed the long-held belief that such explosions are responsible for the creation of several heavy elements found in the universe, such as gold, silver and uranium.
The discovery of metallic hydrogen
Humanitys quest for metallic hydrogen has been a long one. Ever since Eugene Wigner and Hillard Bell Huntington proposed the existence of a metallic form of the lightest element in 1935, scientists everywhere have been trying to synthesise it. This is because metallic hydrogen can potentially function as a superconductor at room temperature. Superconductors (electrical conductors that offer no resistance to the flow of electricity and expel all magnetic fields) currently exist at extremely low temperatures, which are difficult to attain. In fact, most superconductors in use today operate at around 4K (-269.15 OC). A way to achieve superconductivity in a material (apart from cooling it down to a very low temperature) is by applying extremely high pressure to it, which is what most scientists have tried in order to obtain metallic hydrogen. However, all such efforts by scientists caused the hydrogen lattice to rearrange itself and form non-conducting complex solid structures.
In January this year, scientists Isaac Silvera and Ranga Dias from Harvard University claimed to have detected metallic hydrogen by squeezing a hydrogen compound between two flattened, micron-wide diamond tips at an extremely low temperature. The combination of low temperature and high pressure (about 498 times the atmospheric pressure) is said to have given the scientist duo a glimpse of the long-sought metallic hydrogen. However, many members of the science community consider the method (that Silvera and Dias used to detect metallic hydrogen) unreliable, since the conductivity of hydrogen was not measured during the experiment. Thus, while the existence of metallic hydrogen still is not confirmed, the developments made this year will surely help researchers solve this mystery in the future.
A new state of matter: Excitonium
A group of researchers at the University of Illinois at Urbana-Champaign made this breakthrough at the beginning of this month. They proved the existence of a completely new form of matter, called excitonium. Incidentally, the term excitonium had been coined in the 1960s by Bert Halperin, a theoretical physicist at Harvard University.
An exciton is an elementary particle that is supposed to be formed by the pairing of an escaped electron pairs up with the vacancy it leaves behind (a hole). It was theorised about fifty years ago. Excitonium is a condensate of excitons, in which all the particles are at their lowest energy states. Scientists discovered this state of matter when they used a technique called Momentum-resolved Electron Energy-Loss Spectroscopy (M-EELS) to detect and measure the collective excitations of low-energy excitons. This discovery is bound to have a far-reaching impact on how different materials can be manipulated to extract a particular use out of them.
Editing genes using CRISPR-Cas9 technique
Several developments were made in the (relatively) new domain of gene editing. The CRISPR-Cas9 technique is at the forefront when it comes to editing a genome which is an organism’s complete set of DNA, including all of its genes.
Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) is a technique used to identify specific DNA sequences in human, plant and animal genomes. CRISPR-associated endonuclease (Cas9) is an enzyme that can precisely cut a given DNA sequence of an organism. The region that has been edited using CRISPR-Cas9 can then be implanted with a different sequence of DNA to introduce some desired traits in a future generation of the organism. Thus, CRISPR-Cas9 can be used to eliminate undesirable traits and add desirable traits in a highly precise manner and with a significantly low risk.
The low cost and ease of using CRISPR-Cas9 have made it popular amongst many bioscientists who have used it in many innovative ways to obtain possible cures for several genetic and chronic diseases such as some types of cancers, sickle-cell diseases, thalassemia, among others. The most notable use of the technique in 2017 was when scientists successfully replaced a mutated gene in human embryos with a healthy one. The defective gene, MYBPC3 was responsible for causing hypertrophic cardiomyopathy, a potentially fatal heart condition. A CRISPR-Cas9 based method called SHERLOCK (for Specific High Sensitivity Enzymatic Reporter UnLOCKing) also gained prominence this year. SHERLOCK can be used to find out specific genetic information, such as the RNA of disease agents (for instance, the Zika virus) and is fairly inexpensive, costing less than a US dollar per sample.
Despite all the wonders that the CRISPR-Cas9 technique is capable of, it is mired in controversy and patent disputes. Many believe that attempting to tamper with natural creations such as human genomes could have severe ramifications.
Discovery of seven Earth-sized exoplanets
In February 2017, a group of astrophysicists from the University of Liège in Belgium announced the existence of seven Earth-sized exoplanets in the system of the dwarf star, TRAPPIST-1, about 39 light-years away. These planets were detected when they experienced eclipses, which was indicated by a decrease in the brightness of the light originating from TRAPPIST-1.
Out of seven, three planets lie in the stars habitable zone, which is a region with optimum temperatures for the existence of water in its liquid form. These planets cross in front of the star every 6.10, 9.21 and 12.35 days. The sheer number of planets that orbit TRAPPIST-1 increases the chances of finding life in its system, according to various astronomers. Scientists are now preparing to look for escaping hydrogen from the surfaces of these planets, which would indicate the presence of an atmosphere. However, the frequent and powerful stellar flares that are emitted by dwarf stars (like TRAPPIST-1) can destroy a planets atmosphere, eliminating the possibility of life.
It remains to be seen if extraterrestrial life does exist in this system or elsewhere, but with the increased pace of discovery of potentially habitable planets, it seems that we are at the edge of something huge.
Featured Image Credits: VisualHunt