David Appell

When we think of extraterrestrial intelligence that might be out there among the stars, we tend to think of creatures not too unlike us, though maybe with gray skin, probably bald and with big black eyes. We focus on the ...

Ocean fish stocks have been increasingly exploited over time, and remote sensing shows they have declined in the open ocean over the last three decades, particularly in the tropics. But it's uncertain how fish populations ...

The famous "Turing test" of computer science comes from a 1950 paper written by the British computer scientist (and war hero) Alan Turing. There are many variants, but perhaps the most common involves a human asking questions ...

Glimpses of the "gallium anomaly" were first seen in the mid-1990s, but it was first clearly discovered and stated in 2007 by neutrino physicist Carlo Giunti of Italy. The problem is simple to state but potentially very important: ...

Boats passing over smooth water form a pair of diffusion wakes behind them veering off at a certain angle. Turbulence occurs along the line directly behind the boat, but the two diffusion waves are at a theoretical angle ...

Scientists have confirmed the existence of a predicted room temperature superconductor, while explaining the microscopic mechanism that distinguishes it from a similar one discovered several years ago. The work, published ...

Unlike electric charge, as far as we know all mass is positive, and positive masses attract one another. Could negative mass exist, and if so, what would be the ramifications?

Despite all the advertisements for engagement rings and necklace gifts, natural diamonds are imperfect. Their carbon atoms are arranged in a cubic lattice, but they nonetheless contain several types of crystallographic defects ...

Physics is most readily applied to relatively simple systems: a pendulum, two electrons colliding or the structure of the solar system. But when systems become complicated—when many particles interact with one another, in ...

Animals struggle to cool down in extreme heat and high humidity, and heat stress is rising in many regions around the world. This is especially true for people in tropical countries, including populous India. In a new paper ...

El Niños and La Niñas are the third-most dominant influences on Earth's climate, after the sun and the greenhouse effect. But they haven't been easy to decipher or to predict in terms of when they will happen and what exact ...

There is a constant war going on in your body. Working against you are viruses and cancer cells growing uncontrollably, threatening your tissues and organs. Fighting on your side are immune cells such as lymphocytes, a type ...

Olive oil and water do not naturally mix. Water molecules are polar, having a net electric dipole moment due to the bend angle of about 104.5° between the two oxygen-hydrogen bonds. Olive oil is nonpolar due to its long hydrocarbon ...

Vegetarians need not worry yet—plants will be on Earth for a long time to come. But not forever. The sun will ultimately determine the long-term existence of life on Earth. Its total energy output, called luminosity, has ...

Could Earth have seeded Jupiter's moon Europa with bacterial life, where it could have taken hold in Europa's ocean and perhaps evolved into something more? That's the hypothesis of a new paper in the International Journal ...