Astronomers have successfully utilized the James Webb Space Telescope (JWST) to observe the presence of an atmosphere around a terrestrial exoplanet, marking the first such discovery beyond our solar system. Despite its inability to sustain life due to its likely magma ocean, this planet could provide valuable insights into the early geological development of Earth, as both planets share a rocky composition and a history of being molten.

Sara Seager, a planetary scientist at the Massachusetts Institute of Technology in Cambridge who was not part of the study, states that the discovery of a gaseous envelope surrounding an Earth-like planet is a significant achievement in the field of exoplanet research. The Earth’s tenuous atmosphere plays a vital role in supporting life, and the ability to detect atmospheres on comparable rocky planets is a significant milestone in the quest for extraterrestrial life.

JWST is currently studying the planet 55 Cancri e, which orbits a star similar to the Sun at a distance of 12.6 parsecs. It is classified as a super-Earth, meaning it is a terrestrial planet slightly larger than Earth. Specifically, it has a radius approximately twice that of Earth and a mass more than eight times greater. The paper published in Nature1 suggests that the atmosphere of the planet is likely to contain significant amounts of carbon dioxide or carbon monoxide. Additionally, the thickness of the atmosphere is estimated to be “up to a few percent” of the planet’s radius.

A mysterious world
55 Cancri e is also not a good place to live because it is very close to its star—about 1.6 times as close as Earth is to the Sun. Still, Aaron Bello-Arufe, an astrophysicist at the Jet Propulsion Laboratory (JPL) in Pasadena, California, and a co-author of the paper, says, “it’s perhaps the most studied rocky planet.” Its host star is bright at night, and the planet is big for a rocky one, so it’s easier to study than other places outside of the Solar System. “In astronomy, every telescope or other tool you can think of has pointed to this planet at some point,” says Bello-Arufe.

55 Cancribe was studied so much that when JWST was launched in December 2021, engineers pointed the infrared spectrometers of the spacecraft at it to test it. As these instruments soak up infrared wavelengths from starlight, they can find the chemical signatures of gases swirling around planets. Then Bello-Arufe and his coworkers chose to look into it more to find out for sure if the planet had an atmosphere.

Astronomers had changed their minds about 55 Cancri a huge number of times before the most recent observations. In 2004, the planet was found. Scientists first thought it might be the center of a gas giant like Jupiter. Researchers looked at 55 Cancri e as it passed in front of its star3 with the Spitzer Space Telescope in 2011. They found that it is a rocky super-Earth, much smaller and denser than a gas giant.

After some time, scientists found that 55 C was cooler than it should have been for a planet that was so close to its star. This suggests that it probably has an atmosphere. One hypothesis was that the planet is a “water world” with supercritical water molecules all around it. Another was that it has a large, primordial atmosphere mostly made up of hydrogen and helium. But in the end, these ideas were shown to be wrong.

According to Renyu Hu, a planetary scientist at JPL and co-author of the new study, stellar winds would make it difficult for a planet this close to its star to retain volatile molecules in its atmosphere. He says there are still two options. The first was that the planet is completely dry and has a very thin layer of rock vapor in the air. The second reason was that it has a thick atmosphere made up of heavier, less volatile molecules that don’t easily escape.

A better picture
The most recent information shows that 55 Cancrie’s atmosphere has gases made of carbon, which points to option two. Seager says that the team did indeed find evidence of an atmosphere but that more observations are needed to fully understand its make-up, the amounts of gases present, and its exact thickness.

Laura Schaefer is a planetary geologist at California’s Stanford University. She wants to know how the atmosphere of 55 Cancrie affects things below the surface of the planet. The authors of the study say it’s still possible that stellar winds are carrying away parts of the atmosphere. However, rocks melting and releasing gases into the magma ocean could replace the gases.

Scientists have made significant progress in developing a novel clock that relies on minute changes in energy within an atomic nucleus. Conceptually, a nuclear clock has the potential to surpass the precision of the world’s most accurate timekeeping devices, referred to as optical clocks, while also being less susceptible to disruptions.

Additionally, a nuclear chronometer could enable physicists to investigate the fundamental forces of nature using novel approaches. “We will have the capability to investigate situations involving dark matter and fundamental physics that are presently unattainable through alternative means,” states Elina Fuchs, a theoretical physicist at CERN, the particle-physics laboratory in Europe located near Geneva, Switzerland.

The highly anticipated discovery, achieved through a partnership between the Vienna University of Technology and Germany’s national metrology institute, the PTB, in Braunschweig, utilized an ultraviolet laser to induce a transition in the energy levels of a nucleus of the radioactive element thorium-229. The frequency of light that is absorbed and emitted by the nucleus serves as the mechanism for the clock’s ticking. The researchers disseminated their findings in the scientific journal Physical Review Letters on the 29th of April.

“This is significant,” states Adriana Pálffy-Buß, a theoretical physicist affiliated with the University of Würzburg in Germany. Using a laser to drive the transition is a crucial step that signifies the ability to construct a clock.”The achievement represents the combined efforts of numerous scientific organizations over a period of almost fifty years,” states Olga Kocharovskaya, a physicist affiliated with Texas A&M University in College Station.

Exactly on time
So well do optical clocks keep time that they only go off by one second every 30 billion years. To change an electron’s energy state around an atom like strontium, they need a certain frequency of visible light. This frequency controls how fast they tick.

But a nuclear clock would work better. To make the transition more energetic, the protons and neutrons in the nucleus would be raised to a higher energy level. This would use a slightly higher frequency of radiation, which would allow time to be cut even more precisely, making the clock more accurate. A clock like this would also be much more stable than an optical clock, since particles in the nucleus are not as affected by outside fields or temperature as electrons are.

But it has been hard to find a material with the right nucleus. Most nuclei have big energy changes that need a lot more than the push of a tabletop laser. Scientists found out in the 1970s that thorium-229 is different because its first energy state is very close to its ground state. In 2003, physicists suggested using thorium-229 as the building block of a super-stable clock. But they had to find the exact energy of the transition and the laser frequency that went with it, which could not have been predicted with any degree of accuracy using theory. The numbers have been narrowed down in a number of different ways since then.

To see the change, scientists put radioactive thorium atoms into calcium fluoride crystals that were only a few millimeters wide. They used a custom-built laser to scan the expected area and finally found the right frequency: about 2 petahertz (1015 oscillations per second). They were able to identify this frequency by observing the photons released by the nuclei as they returned to a lower-energy state. Thorsten Schumm, an atomic physicist at the Vienna University of Technology and co-author, remembers writing “found it” in big red letters in his lab book at a meeting the next day to talk about the signal that looked promising. He says, “It was very clear.”

The team was 800 times more accurate than the next best attempt when they found the frequency. According to co-author and PTB physicist Ekkehard Peik, since then, a team at the University of California, Los Angeles, has used the same frequency to achieve the same result. He calls it “a very nice confirmation.”

Help with basic physics
Scientists will have to greatly lower the laser’s resolution in order to make the system work as a real clock. This is so that it can reliably stimulate the nucleus at just the right frequency, according to Peik. “Building such a laser remains a big challenge,” says Kocharovskaya. “But there are little doubts that it will be possible in the near future.”

The group says that a thorium-based nuclear clock might be about 10 times more accurate than the best optical clocks if everything goes as planned. “This will be a better clock because it will be more resistant to changes in the outside world,” says Schumm. The clock might be smaller and easier to carry around if the nuclei are in a solid crystal instead of an optical system.

Help with basic physics
Scientists will have to greatly lower the laser’s resolution in order to make the system work as a real clock. This is so that it can reliably stimulate the nucleus at just the right frequency, according to Peik. “Building such a laser remains a big challenge,” says Kocharovskaya. “But there are little doubts that it will be possible in the near future.”

The group says that a thorium-based nuclear clock might be about 10 times more accurate than the best optical clocks if everything goes as planned. “This will be a better clock because it will be more resistant to changes in the outside world,” says Schumm. The clock might be smaller and easier to carry around if the nuclei are in a solid crystal instead of an optical system.

Very accurate optical clocks have made it possible for scientists to do things like measure differences in clock speeds to look into Earth’s gravitational field. Kocharovskaya says that these methods “could get a major boost.”

On a deeper level, physics could also use some help. Says Fuchs that a nuclear clock would be 10,000 times more aware of changes in fundamental constants, like the strength of the strong nuclear and electromagnetic forces. This means they could find possible types of dark matter, an invisible substance that physicists believe makes up 85% of the universe’s matter and is thought to cause tiny changes in the strength of these forces.

Fuchs says, “It’s possible that there’s very “light” dark matter that moves around, which could make these fundamental constants move.” She says that nuclear clocks might be able to pick up on that wiggle because these forces control the energy of their transition, and any change in their strength would change the tick in a way that can be measured. She also says that nuclear clocks could find out if the masses of some particles change over time. Fuchs and her colleagues are already working on their first paper, which is based on the measurement of frequency. She says, “This is pretty exciting for us.”

The World Health Organization (WHO) initiated its global vaccination program in 1974 with the aim of ensuring universal access to vaccines for children worldwide. A recent study indicates that vaccination has had a substantial effect on public health over the past 50 years, resulting in the prevention of millions of deaths.

Initially, the Expanded Programme on Immunization (EPI) by WHO aimed to vaccinate all children against seven diseases, including the now-extinct smallpox. However, the program has now been extended to cover 14 different pathogens.

The recent study analyzed the effects of the vaccines for these diseases on both local and worldwide public health from the start of the EPI in June 1974 until its 50th anniversary in 2024.

These estimates were obtained through the application of mathematical and statistical modeling to determine three important metrics: the quantity of prevented deaths, the amount of gained life-years, and the duration of improved overall health.

According to the findings of the 22 models combined, global vaccination efforts over the past 50 years have had a significant effect. It is estimated that immunization has saved approximately 154 million lives since 1974, replacing death with an average of 66 years of good health per person.

The program’s most significant influence in terms of age seems to be on the youngest members of society. Modeling analysis revealed that out of the estimated 154 million deaths that were prevented, 101 million were specifically among infants aged less than one year. Additionally, it was indicated that vaccination accounted for 40 percent of the decrease in worldwide infant mortality, making it the primary factor in that reduction.

Although all of the vaccines examined had an effect, the measles vaccine had the most notable influence, despite the recent resurgence of measles.

“Measles vaccination contributed to 60% of the overall benefits of vaccination over the span of 50 years, making it the primary factor in saving lives,” stated Dr. Andrew Shattock, the leader of the study.

The authors assert that the results serve as evidence of the potential that can be realized through collaboration, and advocate for continued efforts.

“Vaccines are one of the most influential innovations in human history, as they have the ability to prevent diseases that were once feared,” stated Dr. Tedros Adhanom Ghebreyesus, the Director-General of the World Health Organization (WHO). Vaccines have played a crucial role in eradicating smallpox and bringing polio to the verge of elimination. Furthermore, the development of vaccines against diseases such as malaria and cervical cancer has allowed us to make significant progress in combating these illnesses.

“Through ongoing research, investment, and collaboration, we have the potential to preserve millions of additional lives both presently and over the course of the next five decades.”