As far as physical science and space exploration is concerned, February 2021 was one hell of a month. There were several interesting discoveries in physics and achievements in spaceflight. Let’s have a look at the top scientific achievements in February 2021.
Mars had the busiest month in the past 47 years. Three countries (the United States, the UAE, and China) successfully reached the Red Planet in a span of two weeks. The countries had launched their respective missions in the narrow launch window of July 2020. The Emirates Mars Mission of the UAE carried a spacecraft called Hope to study the weather patterns on Mars. China’s Tianwen-1 mission carries a lander, a rover, and an orbiter. The Chinese will land on Mars in April this year. Finally, America’s Mars 2020 mission carried the Perseverance rover that successfully landed on the Martian surface on February 18.
The landing of the fifth American rover on Mars was unique because this was the first time the EDL (Entry, Descent, and Landing) was recorded by cameras onboard the spacecraft. The breathtaking footage shows the parachute deployment, the divert maneuver, the skycrane maneuver, and the Perseverance rover’s touchdown. Besides that, NASA also released thousands of raw images captured by the rover in its first week on Mars.
Perseverance landed in the Jezero crater, a 45-km wide basin that might have been flooded in the past. According to scientists, the crater is one of the best sites to search for the past microbial life on Mars. If life existed in that crater, Perseverance has all the tools to search for it. The rover is now preparing for its first drive on the surface of Mars. After a few weeks, it will deploy the Mars Helicopter Ingenuity.
Swarm of black holes
Two astronomers from the Paris Institute of Astrophysics working on data from the Hubble Space Telescope and ESA’s Gaia spacecraft have found dozens of black holes in the globular cluster NGC 6397. Eduardo Vitral and Gary A. Mamon reported their results in the journal of Astronomy and Astrophysics.
NGC 6397 is a spherical cluster of old stars – a globular cluster that orbits the Milky Way and perhaps predates its formation. It is 13 billion years old and contains about 250,000 old and dim stars. Since the average life of most of the bright blue, white, and yellow-colored stars is less than 10 billion years, most of the stars in NGC 6397 have decayed into black holes or other stellar remnants.
So the cluster is a likely candidate to harbor an intermediate-mass black hole. Indeed, earlier studies had suggested that a black hole of about 600 solar masses anchored the center of NGC 6397. Since a black hole has such an enormous gravitational pull, not even light can escape it. Hence, we can only detect the presence of a black hole in space using indirect means. One of them is measuring the velocity of the nearby stars. The faster the star moves, the greater the gravitational force, and more is the mass present in the cluster.
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Observations by Mamon and Vitral showed that the stars were not under the influence of a single gargantuan dark object. An extended dark source instead influenced them. “Our analysis indicated that the orbits of the stars are close to random throughout the globular cluster, rather than systematically circular or very elongated,” Dr. Mamon told New York Times. According to models of stellar evolution, Dr. Mamon said, about two-thirds of this dark stuff would be black holes, with an average mass of 20 suns. The rest of the dark material would be remnants of dead stars, such as white dwarfs or neutron stars.
Mr. Vitral added: “Our discovery of this invisible concentration in a core-collapse globular cluster is surely something that makes us wonder about many ideas of intermediate-mass black hole formation!”
A rare Higgs decay
Particle physicists working at CERN observed a rare decay of the Higgs boson, expanding our understanding of the quantum universe. Scientists found evidence of the massive particle decaying into two leptons and a photon. The decay of the Higgs boson into two photons was previously known. This newly discovered decay channel of the Higgs particle is known as the Dalitz decay.
James Beachum, a particle physicist working with the ATLAS experiment at CERN said, “In this type of decay, after its uber-short life, the Higgs boson quickly turns into one photon and what scientists call a “virtual photon.” That “virtual photon,” also known as an “off-shell photon” then immediately turns into something like, in this case, two leptons. This “virtual photon,” has a very small non-zero mass, while regular photons are completely massless.”
Leptons are the elementary fermions in the standard model that are do not participate in any strong interaction. There are six leptons in the standard model: electron, muon, tau, electron-neutrino, muon-neutrino, and tau-neutrino. To read more about the basics of the Higgs boson, the standard model, and the Dalitz decay, read this article.
“By studying rare decays like this, researchers can explore the possibility of new physics that stretches beyond the Standard Model. The Standard Model explains a lot of things about our physical universe, but it doesn’t include gravity or dark matter,” Beacham said. Dark matter, which emits no light and cannot be directly observed, is thought to make up about 80% of all matter in the known universe, but scientists do not yet know exactly what it is.
More in particle physics
- The concept of Feynman diagrams in physics
- What is the standard model of particle physics?
- The experience of an internship at CERN’s LHC
The Ramanujan machine
We have been using computers for decades now. Computer programming and algorithms have definitely played an unmatchable role in advancing our mathematical and scientific calculations. The conventional way of our computer usage is to pose a mathematical problem to the computer in the form of equations from our side. Then the computer performs a set of algorithms to provide us the solution to that particular problem. However, the Ramanujan machine works in the opposite direction. Ramanujan machine is such a set of out-of-the-box algorithms where our input is a solution instead of a problem. We are expecting the computer to provide us with a set of conjectures related to that specific solution!
The Ramanujan machine was developed by scientists from Technion- Israel Institute of Technology, and their results were reported on Feb. 3 in the journal Nature (You can find the arxiv PDF of the research paper here). The machine has been named after Srinivasan Ramanujan who came up with numerous novel equations and identities in his life, including the equations leading to the value of pi, and then left those equations to be solved by formally trained mathematicians in the future.
Conjectures are undoubtedly a major step in making discoveries in any branch of science. The Ramanujan Machine aims to identify promising conjectures in the first place, which different techniques can then verify. The algorithm developers have also set up a website, RamanujanMachine.com, to share the conjectures that get generated. They are also looking to collect attempted proofs from anyone who’d like to take an opportunity at discovering a new theorem.
More in mathematics:
- A problem that took 358 years to be solved
- Ramanujan’s top contributions to mathematics
- The extraordinary work of the brilliant Carl Jacobi
According to a recent theory, aquatic worlds in Milky Way could be a common occurrence. The new theory called Pebble Accretion claims that our galaxy could be full of rocky worlds covered in oceans and continents similar to the Earth – raising the possibility the galaxy is teeming with alien life.
Current theories suggest that liquid water arrived on Earth by chance from a distant icy comet. Now, Danish scientists say the water was there from the start, and the same applies to Venus and Mars – both of which may have had surface water in the distant past.
Using a computer model, Anders Johansen and his team calculated that a planet around a young star could start forming from ice pebbles after about 5 million years. The study indicates that it was millimeter-sized dust particles of ice and carbon – which are known to orbit around all young stars in the Milky Way – that 4.5 billion years ago accreted in the formation of what would later become Earth.
Earth then grew faster and faster until, after five million years, it became as large as we know it today – along the way, the temperature on the surface rose sharply. The ice in the pebbles started to evaporate on the way down to the surface as it heated up – so that, today, only 0.1% of the planet is made up of water, even though 70% of Earth’s surface is covered by water, the authors explained.
The water molecule H2O is found everywhere in our galaxy, and this theory, therefore, opens up the possibility that other planets may have been formed in the same way as Earth, Mars, and Venus, Johansen speculated.
Cygnus X-1 is much bigger
According to the latest research, Cygnus X-1, the first black hole to be discovered, is much more massive than previously thought. Cygnus X-1 was discovered in 1974 by a pair of Geiger counters sent in space. Not only that, the new research that uses radio astrometry points out that the black hole is much farther than previously thought. The research paper published in the journal Science proposes a whole new black hole mass for Cygnus X-1 – 21.2 ± 2.2 solar masses. For your reference, one solar mass or the Sun’s mass is nearly 2 x 1030 kg.
The credit for correcting this wrong goes to an international team of astronomers that used the Very Long Baseline Array. VLBA is a continent-sized radio telescope made up of 10 dishes spread across the United States and helps measure distances in space.
Learn Astrophysics at Home
Did you always want to learn how the universe works? Read our 30-article Basics of Astrophysics series absolutely free of cost. From the popular topics such as stars, galaxies, and black holes to the detailed concepts of the subject like the concept of magnitude, the Hertzsprung Russell diagram, redshift, etc., there is something for everyone in this series. All the articles are given here. Happy reading!