Are we alone? Probably not. After all, astronomers have already found 4,001 confirmed exoplanets in our Milky Way galaxy, and expect there to be over 50 billion exoplanets out there. For scientists gathering in Paris today, the question is different: why haven't we made contact with alien civilizations?

What is the Fermi Paradox and the "Great Silence?"

Italian physicist Enrico Fermi asked 'where is everybody?' back in 1950 in what's now called the Fermi Paradox. It addresses a contradiction in astronomy, and can be summarized thus: if extraterrestrial life and even intelligent alien civilizations are not just likely, but highly probable, then why have none of them been in contact with us? Are there biological or sociological explanations for this "Great Silence?"

"We are very interested in the scientific approach used in the analysis of the Fermi Paradox and the search for intelligent life in the universe," said Cyril Birnbaum and Brigitte David at the Cité des Sciences et de l'Industrie (Cité), the science museum in Paris that's hosting today's meeting. "The question 'Are we alone?' affects us all, because it is directly related to humanity and our place in the cosmos."

Today there's a Press Release provided by the University of Bristol about comb jellies from the Cambrian, found outcrops south of Kunming in the Yunnan Province, South China by Professor Hou Xianguang, co-author of the study.

Of interest, given the recent release of Michael Behe's new book, Darwin Devolves, is the following statement:

The study shows how comb jellies evolved from ancestors with an organic skeleton, which some still possessed and swam with during the Cambrian. Their combs evolved from tentacles in polyp-like ancestors that were attached to the seafloor. Their mouths then expanded into balloon-like spheres while their original body reduced in size so that the tentacles that used to surround the mouth now emerges from the back-end of the animal.

"With such body transformations, I think we have some of the answers to understand why comb jellies are so hard to figure out. It explains why they have lost so many genes and possess a morphology that we see in other animals," added co-author Dr. Luke Parry.

Two days ago, sunspot AR2736 didn't exist. Now the rapidly-growing active region (movie) stretches across more than 100,000 km of the solar surface and contains multiple dark cores larger than Earth. Moreover, it has a complicated magnetic field that is crackling with C-class solar flares. The sunspot is inset in this magnetic map of the sun from NASA's Solar Dynamics Observatory:

Research led by the University of Southampton suggests that 'rogue' waves are occurring less often, but becoming more extreme.

Scientists have, for the first time, used long-term data from a wide expanse of ocean to investigate how these rare, unexpected and hazardous ocean phenomena behave. Their findings are published in the journal Scientific Reports.

Waves are classed as 'rogue' when they are over twice the height of the average sea state around them. From trough to peak, past observations have put some at over 30 metres high. The fiercest are capable of damaging or sinking ships, can wound or kill crew members and on occasions have swept people off the shoreline and out to sea.

A team of engineers and oceanographers from the University of Southampton, together with researchers from The National Oceanography Centre (NOC), examined over 20 years of information (sourced between 1994-2016) from 15 buoys which provide surface data along the US western seaboard - stretching from Seattle in the north, to San Diego in the south.
The data showed instances of rogue waves vary greatly, depending on the area of sea and time period focused on. On average though, the team found instances of rogue waves (across the two decade window) fell slightly, but that rogue wave size, relative to the background sea, increased by around one per cent year-on-year.

Computer scientists at the University of California, Davis, and the California Institute of Technology have created DNA molecules that can self-assemble into patterns essentially by running their own program. The work is published March 21 in the journal Nature.

"The ultimate goal is to use computation to grow structures and enable more sophisticated molecular engineering," said David Doty, assistant professor of computer science at UC Davis and co-first author on the paper.

The system is analogous to a computer, but instead of using transistors and diodes, it uses molecules to represent a six-bit binary number (for example, 011001). The team developed a variety of algorithms that can be computed by the molecules.

"We were surprised by the versatility of algorithms we were able to design, despite being limited to six-bit inputs," Doty said. The researchers were able to design and run 21 algorithms over the course of the experiments, demonstrating the potential of the system, he said.

Working initially as postdoctoral scholars with Professor Erik Winfree at Caltech, Doty and co-lead author Damien Woods, now at Maynooth University, Ireland, designed a library of short pieces, or tiles, of DNA. Each DNA tile consists of 42 bases (A, C, G or T) arranged in four domains of 10-11 bases. Each domain can represent a 1 or 0 and can stick to some of the domains on other tiles. No two tiles are a complete match.

In the blockbuster Terminator movie franchise, an evil robot morphs into different human forms and objects and oozes through narrow openings, thanks to its "liquid-metal" composition. Although current robots don't have these capabilities, the technology is getting closer with the development of new liquid metals that can be manipulated in 3-D space with magnets. Reported in ACS Applied Materials & Interfaces, the materials could someday find applications in soft robotics.

Metals that are liquids at room temperature, such as gallium and certain alloys, have unique properties including high conductivity, low melting point and high deformability. These properties make them attractive for use in soft robots and flexible electronics. By adding magnetic particles, such as nickel or iron, researchers can produce liquid metals that they can manipulate with magnets. However, because of their high surface tension, most magnetic liquid metals can only move horizontally, and they must be immersed completely in liquid to avoid forming a paste. Liang Hu, Jing Liu and colleagues wanted to make a magnetic liquid metal that they could move and stretch both horizontally and vertically, without needing to put the material completely in a liquid.

To do so, the researchers first worked with the material submersed in liquid. They added iron particles to a droplet of a gallium, indium and tin alloy immersed in hydrochloric acid. A gallium oxide layer formed on the droplet surface, which lowered the surface tension of the liquid metal. When the team applied two magnets in opposite directions, they could stretch the droplet to almost four times its resting length. They could also manipulate the liquid metal to connect two immersed, horizontal electrodes and, by virtue of its conductive properties, light up an LED bulb. The liquid metal could even stretch vertically and then move horizontally to connect two electrodes-the upper one exposed to air, and the lower one in the hydrochloric acid. This demonstrated that the material didn't have to be fully immersed in liquid. In this way, the magnetic liquid metal was reminiscent of an upright walking amphibian, the researchers say.

According to new research carried out by Testbiotech, the United States Department of Agriculture (USDA) has already given non-regulated status to more than 20 plants genetically engineered with so-called genome editing techniques. None of the applications registered at the USDA were referred for further more detailed assessment.

The Testbiotech report published today shows that there are however significant differences in methods of production, traits and risks of the non-regulated plants in comparison to those derived from conventional breeding.

These differences are not caused by the newly introduced gene sequences but by e.g. the patterns of genetic changes. 'Gene-scissors' such as CRISPR/Cas can delete whole families of gene variants all at once - this is either impossible or barely possible with current conventional breeding methods. A further specific difference: in a first step, older methods such as the 'gene gun' (biolistic method) or gene transfer via agrobacterium tumefaciens are commonly used. However, the USDA completely ignores these differences to conventional breeding.

Can two versions of reality exist at the same time? Physicists say they can - at the quantum level, that is.

Researchers recently conducted experiments to answer a decades-old theoretical physics question about dueling realities. This tricky thought experiment proposed that two individuals observing the same photon could arrive at different conclusions about that photon's state - and yet both of their observations would be correct.

For the first time, scientists have replicated conditions described in the thought experiment. Their results, published Feb. 13 in the preprint journal arXiv, confirmed that even when observers described different states in the same photon, the two conflicting realities could both be true. [The Biggest Unsolved Mysteries in Physics]

"You can verify both of them," study co-author Martin Ringbauer, a postdoctoral researcher with the Department of Experimental Physics at the University of Innsbrück in Austria, told Live Science.

Experiments show electric field can modify silicate glass, causing parts to melt while remaining solid elsewhere; discovery suggests heat in glass could be produced on a very fine scale, could point to performance challenges for devices that use glass

Characterizing and predicting how electrically-heated silicate glass behaves is important because it is used in a variety of devices that drive technical innovations. Silicate glass is used in display screens. Glass fibers power the internet. Nanoscale glass devices are being deployed to provide breakthrough medical treatments such as targeted drug-delivery and re-growing tissue.

The discovery that under certain conditions electrically-heated silicate glass defies a long-accepted law of physics known as Joule's first law should be of interest to a broad spectrum of scientists, engineers, even the general public, according to Himanshu Jain, Diamond Distinguished Chair of the Department of Materials Science and Engineering at Lehigh University.

Some bacteria use tails, or flagella, to swim through liquids-including those in our bodies. However, new research published today in PLOS Biology reveals a surprisingly drastic measure taken by some bacteria when facing starvation: they eject their flagella, leaving themselves paralyzed, but conserving energy so they can stay alive.

The research team, led by Imperial College London in collaboration with researchers from the Francis Crick Institute, the University of Leiden, and Justus-Liebig-Universität Giessen, say this is the first time such curious behaviour has been observed in bacteria.

The serendipitous discovery was made when the team were collecting detailed images of the 'motors' that drive flagella in a group of bacteria that includes various harmful species, including Vibrio cholerae, which causes cholera.