Toggle light / dark theme

Ever since Kepler’s observation in the 17th century that sunlight is one of the reasons that the tails of comets to always face away from the sun, it has been understood that light exerts pressure in the direction it propagates. Radiation pressure is produced by the momentum carried by light, and it plays a crucial role in a variety of systems, from atomic to astronomical scales.

In a recent theoretical paper, a group from the RIKEN Center for Emergent Matter Science in Japan showed that density in non-uniform optical fields has an unusual component, which is orthogonal to the propagation direction of and is proportional to the optical spin, which means the degree of circular polarization. They predicted that this spin momentum would produce a transverse spin-dependent optical force, a few orders of magnitude weaker than the usual .

Now, based on the theoretical work, a group from RIKEN, the University of Bristol, and other institutions have used an extremely precise technique to experimentally verify that light does in fact exert the extraordinary perpendicular force, which is determined by the polarization of the light. The research has been published in Nature Physics.

Read more

Every year, the NASA Innovative Advanced Concepts (NIAC) program puts out the call to the general public, hoping to find better or entirely new aerospace architectures, systems, or mission ideas. As part of the Space Technology Mission Directorate, this program has been in operation since 1998, serving as a high-level entry point to entrepreneurs, innovators and researchers who want to contribute to human space exploration.

This year, thirteen concepts were chosen for Phase I of the NIAC program, ranging from reprogrammed microorganisms for Mars, a two-dimensional spacecraft that could de-orbit space debris, an analog rover for extreme environments, a robot that turn asteroids into spacecraft, and a next-generation exoplanet hunter. These proposals were awarded $100,000 each for a nine month period to assess the feasibility of their concept.

Of the thirteen proposals, four came from NASA’s own Jet Propulsion Laboratory, with the remainder coming either from other NASA bodies, private research institutions, universities and aerospace companies from around the country. Taken as a whole, these ideas serve to illustrate of the kinds of missions NASA intends to purse in the coming years, as well as the cutting-edge technology they hope to leverage to make them happen.

Read more

It takes a bold person to declare that interstellar travel is now within our grasp. Physicist Stephen Hawking has shown that he is just that, taking part in the Breakthrough Starshot initiative. The project has announced a $100m research programme to investigate the technology of using light to propel spacecraft out of the solar system to explore neighbouring stars.

For the first time in human history, interstellar travel is a realistic and achievable aspiration, and not just the playground of science fiction.

So what has changed that makes interstellar travel achievable? First of all, clear expectations. This is not about a great big spaceship with a colony of astronauts travelling for generations to settle a planet around a distant star. Neither is it about faster-than-light travel, tunnelling through wormholes to arrive at the other side of the universe in an instant of time. This is about technology that already exists, or nearly exists, being applied in new and exciting ways.

Read more

Ever notice how maps of the large structures of the Universe look like maps of the brain or a Pollock painting?


On the grandest scale, our universe is a network of galaxies tied together by the force of gravity. Cosmic Web, a new effort led by cosmologists and designers at Northeastern’s Center for Complex Network Research, offers a roadmap toward understanding how all of those tremendous clusters of stars connect—and the visualizations are stunning.

The images below show us several hypothetical architectures for our universe, built from data on 24,000 galaxies. By varying the construction algorithm, the researchers have designed cosmic webs that link up in a number of different ways; based on the size, proximity, and relative velocities of individual galaxies. I call it God View.

It may sound like sci-fi. But millions and millions of dollars are pouring into projects to mine asteroids and the moon. And with a space gold rush comes space pirates.

With trillions of dollars worth of minerals lying just under the moon’s surface or spinning around the solar system inside asteroids, space mining is big business.

Well, big potential business. No one has dug nickel out of an asteroid or scooped any tantalum from the lunar dust—at least not for profit. Before space miners can get drilling, they need to invent specialized industrial robots, set up orbital outposts and—arguably most importantly—convince investors, workers, and prospective buyers that space minerals are worth the cost and effort of mining them.

Read more