An Earth-like planet has been discovered around the sun’s nearest star
A third planet has been found circling Proxima Centauri, the nearest star to the Sun. The newly discovered planet, known as Proxima Centauri d, is likely smaller than Earth and may contain liquid water seas.
By monitoring minuscule fluctuations in the spectrum of light released by the star as the planet’s gravity tugged at it throughout orbit, astronomer Joo Faria and his team discovered Proxima Centauri d. The researchers employed the Echelle Spectrograph for Rocky Exoplanets and Stable Spectroscopic Observations at the European Southern Observatory’s Very Large Telescope at Cerro Paranal, Chile, which is a system of four 8.2-metre telescopes. The results were released on February 10th (J. P. Faria et al. Astron. Astrophys. 658, A115; 2022).
“Knowing that our Sun’s closest star neighbor is home to three tiny planets is exciting,” says Elisa Quintana, an astronomer at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Because of their close closeness, this is an ideal system for additional research to better understand their nature and how they evolved.”
Guinea worm illness is on the verge of being eradicated.
In 2021, just 14 human instances of Guinea worm infection – a parasite that produces painful skin sores — were documented, giving optimism that the condition will be eliminated shortly. The figure is the lowest ever for an illness that was present in more than 20 nations and affected 3.5 million people each year as recently as the 1980s (see ‘On the way out’). “It’s fairly incredible,” says Adam Weiss, director of the Carter Center’s Guinea Worm Eradication Program, based in Atlanta, Georgia. The figures were released by the center in late January.
According to Weiss, the decline — which is about 50% lower than the 27 instances recorded in 2020 — is the outcome of a nearly 40-year campaign by international organizations and state governments to eradicate Guinea worm from the planet. If the plan succeeds, smallpox and rinderpest (a virus that mostly afflicted cattle and buffalo) would be the first illnesses in human history to be purposely exterminated.
For the parasite, there is no known therapy or vaccination. Rather of eradicating the disease, eradication initiatives have concentrated on preventing it from spreading. However, since the parasite still has a reservoir in animals, eradication may take a long time, if it can be done at all, according to some experts.
A new upper bound on the mass of the elusive neutrino has been established
Physicists have taken another step in determining the mass of the neutrino, one of the most enigmatic of all fundamental particles.
Neutrinos have a maximum mass of 0.8 electronvolts, according to researchers at the Karlsruhe Tritium Neutrino (KATRIN) experiment in Germany (The KATRIN Collaboration Nature Phys. 18, 160–166; 2022). Although there has been indirect evidence suggesting the particles should be lighter than 1 electronvolt, this is the first time it has been shown in a direct measurement.
The neutrinos generated by the nuclear disintegration of tritium, a radioactive isotope of hydrogen, are weighed by KATRIN (shown). When a tritium nucleus decays into helium, an electron and a neutrino are ejected. Although the neutrino is lost, the electron is channeled into a 23-metre-long, blimp-shaped steel vacuum chamber, where its energy is carefully measured.
The electron transports practically all of the energy released by the breakdown of tritium, although the neutrino loses some. The mass of the particle may be calculated using the value of this deficit.
KATRIN has only been able to establish an upper constraint on the mass of the neutrino so far. However, after the data collection is completed in 2024, experts believe it will be possible to establish a definite measurement.
PHOTO CREDIT: An artist’s impression of the newly discovered planet orbiting Proxima Centauri.Credit: ESO/L. Calçada