David Appell

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 ...

Cosmic rays seen at Earth show a wide range of particle energies, from 107 electron-volts (eV) to more than 1020 eV, the latter being about the same as the kinetic energy of a 450 gram football (soccer ball) being kicked ...

About a billion years ago, Earth started to come into its own. It was past the awkwardness of its younger years full of growing pains and turmoil: comet strikes and slimy water, including the Great Oxidation Event that flipped ...

When you're looking for signs of extraterrestrial intelligence, it helps to know what you're looking for and to go about it in the most efficient way. But work so far has generally not done so, writes Benjamin Zuckerman, ...