Astronomers agree that planets are born in protoplanetary disks — rings of dust and gas that surround young, newborn stars. While hundreds of these disks have been spotted throughout the universe, observations of actual planetary birth and formation have proved difficult within these environments. 

Now, astronomers at the Center for Astrophysics | Harvard & Smithsonian have developed a new way to detect these elusive newborn planets — and with it, "smoking gun" evidence of a small Neptune or Saturn-like planet lurking in a disk. The results are described today in The Astrophysical Journal Letters.

"Directly detecting young planets is very challenging and has so far only been successful in one or two cases," says Feng Long, a postdoctoral fellow at the Center for Astrophysics who led the new study. "The planets are always too faint for us to see because they’re embedded in thick layers of gas and dust."

Scientists instead must hunt for clues to infer a planet is developing beneath the dust.

"In the past few years, we've seen many structures pop up on disks that we think are caused by a planet's presence, but it could be caused by something else, too" Long says. "We need new techniques to look at and support that a planet is there."

For her study, Long decided to re-examine a protoplanetary disk known as LkCa 15. Located 518 light years away, the disk sits in the Taurus constellation in the sky. Scientists previously reported evidence for planet formation in the disk using observations with the ALMA Observatory.

Long dove into new high-resolution ALMA data on LkCa 15, obtained primarily in 2019, and discovered two faint features that had not previously been detected.

About 42 astronomical units out from the star — or 42 times the distance Earth is from the Sun — Long discovered a dusty ring with two separate and bright bunches of material orbiting within it. The material took the shape of a small clump and a larger arc and was separated by 120 degrees.

Long examined the scenario with supercomputer models to figure out what was causing the buildup of material and learned that their size and locations matched the model for the presence of a planet.

"This arc and clump are separated by about 120 degrees," she says. "That degree of separation doesn’t just happen — it’s important mathematically."

Long points to positions in space known as Lagrange points, where two bodies in motion — such as a star and orbiting planet — produce enhanced regions of attraction around them where the matter may accumulate.

"We're seeing that this material is not just floating around freely, it's stable and has a preference where it wants to be located based on physics and the objects involved," Long explains.

In this case, the arc and clump of material Long detected are located at the L4 and L5 Lagrange points. Hidden 60 degrees between them is a small planet causing the accumulation of dust at points L4 and L5.

The results show the planet is roughly the size of Neptune or Saturn, and around one to three million years old. (That's relatively young when it comes to planets.)

Directly imaging the small, newborn planet may not be possible any time soon due to technology constraints, but Long believes further ALMA observations of LkCa 15 can provide additional evidence supporting her planetary discovery.

She also hopes her new approach for detecting planets — with material preferentially accumulating at Lagrange points — will be utilized in the future by astronomers.

"I do hope this method can be widely adopted in the future," she says. "The only caveat is that this requires very deep data as the signal is weak."

Long recently completed her postdoctoral fellowship at the Center for Astrophysics and will join the University of Arizona as a NASA Hubble Fellow this September.

This study involved high-resolution ALMA observations taken with Band 6 (1.3mm) and Band 7 (0.88mm) receivers. 

The new study could have big implications for genome research, evolutionary biology, physics, and cosmology. 

Genetic mutations could be predicted before they occur using a new law of physics, according to a study from the University of Portsmouth, England.

The paper finds the second law of information dynamics, or ‘infodynamics’, behaves differently from the second law of thermodynamics - a discovery that could have massive implications for future developments in genome research, evolutionary biology, supercomputing, big data, physics, and cosmology. 

Lead author Dr. Melvin Vopson is from the University’s School of Mathematics and Physics. He said: “In physics, there are laws that govern everything that happens in the universe, for example how objects move, how energy flows, and so on. Everything is based on the laws of physics. 

“One of the most powerful laws is the second law of thermodynamics, which establishes that entropy – a measure of disorder in an isolated system – can only increase or stay the same, but it will never decrease.”

This is an undisputed law linked to the arrow of time, which shows that time only goes one way. It flows in a single direction and can’t go backward.

He said: “Imagine two transparent glass boxes. On the left side, you have red gas molecules, which you can see, like red smoke. On the right side, you have blue smoke, and in between, them is a barrier. If you remove the barrier, the two gases will start mixing and the color will change. There is no process that this system can undergo to separate itself from blue and red again.

“In other words, you cannot lower the entropy or organize the system to how it was before without energy expense, because the entropy only stays constant or increases over time.”

Dr. Vopson is an information physicist. His work explores information systems, which can be anything from the disc in a laptop to the DNA and RNA in living organisms. This paper was written in collaboration with Dr. Serban Lepadatu from the University of Central Lancashire.

Dr. Vopson added: “If the second law of thermodynamics states that entropy needs to stay constant or increase over time, I thought that perhaps information entropy would be the same.

“But what Dr. Lepadatu and I found was the exact opposite – it decreases over time. The second law of information dynamics works exactly in opposition to the second law of thermodynamics.”

Dr. Vopson claims this could be what drives genetic mutations in biological organisms. 

“The worldwide consensus is that mutations take place at random and then natural selection dictates whether the mutation is good or bad for an organism”, he explained. If the mutation is beneficial for an organism, it will be kept. 

“But what if there is a hidden process that drives these mutations? Every time we see something we don’t understand, we describe it as ‘random’ or ‘chaotic’ or ‘paranormal’, but it’s only our inability to explain it. 

“If we can start looking at genetic mutations from a deterministic point of view, we can exploit this new physics law to predict mutations - or the probability of mutations - before they take place.”

Dr. Vopson and colleagues analyzed real Covid-19 (Sars-CoV-2) genomes and found that their information entropy decreased over time: “The best example of something that undergoes a number of mutations in a short space of time is a virus. The pandemic has given us the ideal test sample as Sars-CoV-2 mutated into so many variants and the data available is unbelievable.

“The Covid data confirms the second law of infodynamics and the research opens up unlimited possibilities. Imagine looking at a particular genome and judging whether a mutation is beneficial before it happens. This could be game-changing technology which could be used in genetic therapies, the pharmaceutical industry, evolutionary biology, and pandemic research.”