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Category: space – Page 1,110

Why is space three-dimensional?

(Phys.org)—The question of why space is three-dimensional (3D) and not some other number of dimensions has puzzled philosophers and scientists since ancient Greece. Space-time overall is four-dimensional, or (3 + 1)-dimensional, where time is the fourth dimension. It’s well-known that the time dimension is related to the second law of thermodynamics: time has one direction (forward) because entropy (a measure of disorder) never decreases in a closed system such as the universe.

In a new paper published in EPL, researchers have proposed that the second law of thermodynamics may also explain why is 3D.

“A number of researchers in the fields of science and philosophy have addressed the problem of the (3+1)-dimensional nature of space-time by justifying the suitable choice of its dimensionality in order to maintain life, stability and complexity,” coauthor Julian Gonzalez-Ayala, at the National Polytechnic Institute in Mexico and the University of Salamanca in Spain, told Phys.org.

A Tesla Model S equipped with a robotic arm for your wheelchair [Video]

A Germany-based company, Paravan, is a leader in the electric wheelchair market and related accessories to adapt vehicles for people with disabilities. While they mostly work with vans and trucks, their latest product makes almost any car with enough trunk space extremely practical for someone using a wheelchair.

They installed it in a Tesla Model S to illustrate the functionalities of the product and the range of vehicles it can be installed on.

A robotic arm, called Robot 3000, can automatically lift a wheelchair (up to 25 kg – 55 lbs) from the trunk of a vehicle, then it moves the chair to the driver’s side and extends it all the way to the driver’s door.

About Sky Line


In.
1979, Arthur C. Clarke wrote a novel about an elevator to space. This.
is the story of the people who intend to build it.

SKY LINE is not just a story about trying to build the largest thing ever, it’s a story about our impulse to push limits and chase dreams, even when the results might not be seen until long after we’re gone. What drives a person to devote his life to pursuits that may take generations to achieve?

We set out to answer that question when we first went to Seattle to begin filming the folks involved in the Space Elevator Conference. We didn’t have much of a plan, but we knew everyone had a story – and we found the people that became the backbone of this film. For several years, we would revisit these eccentric and brilliant characters, until we had cobbled together a film called SKY LINE.

Tim Peake Controls An Earth Robot From Space — Rover In U.K. Skillfully Driven

Astronaut Tim Peake controlled a robot from the International Space Station (ISS). However, the robot wasn’t in space, but was located on Earth. The experiment was meant to prepare astronauts and technicians for future human-robotic missions to the Moon, Mars, and other celestial bodies.

As part of a unique experiment, astronaut Tim Peake successfully maneuvered a robot located on Earth from the ISS. The British astronaut took control from the Earth-based team and steered the robot on a simulated Martian landscape. The experiment took place at Airbus Defence and Space in Stevenage, dubbed “Mars Yard.”

The experiment, titled “Supervisory Control of Mars Yard Rover” or SUPVIS-M for short, was designed to one day allow humans, more specifically astronauts, sitting on board ISS or other deep space vehicles, to reliably control robots or machines over vast distances. The experiment is part of Europe’s METERON (Multipurpose End-To-end Robotics Operations Network) project. The overall idea is develop and optimize tasks and directional control.

Cassini discovers that lake on Saturn’s moon is liquid methane

The moon has three large seas and a number of smaller lakes connected by rivers and rivulets located in its northern hemisphere, and one large lake in the south. NASA researchers previously believed the liquid to be ethane, which is produced when “sunlight breaks methane molecules apart”, said Alice Le Gall, a member of the Cassini radar team who led the study into the makeup of the moon’s liquid reservoirs.

Using radar observations of the heat given off by Ligeia Mare, as well as data from a 2013 experiment that bounced radio signals off of the sea, the team determined the compositions of the liquid sea and the sea bed by separating each of their contributions to the sea’s observed temperature.

This image from Cassini shows Ligeia Mare, the second largest known body of liquid on Titan.

Physicists detect the enigmatic spin momentum of light

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.

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