Rare hunting scene raises questions over polar bear diet
A polar bear chases a reindeer into the water, drags it ashore and devours it, in a striking scene caught on film for the first time.
A polar bear chases a reindeer into the water, drags it ashore and devours it, in a striking scene caught on film for the first time.
Ecology
Nov 28, 2021
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The planet urgently needs to transition to a green economy because fossil fuel pollution risks pushing the Earth into a lasting and dangerous "hothouse" state, researchers warned on Monday.
Environment
Aug 6, 2018
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There's something going on beneath the surface of Jupiter's icy moon Europa. But what?
Space Exploration
Sep 23, 2016
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The idea of terraforming Mars – aka "Earth's Twin" – is a fascinating idea. Between melting the polar ice caps, slowly creating an atmosphere, and then engineering the environment to have foliage, rivers, and standing ...
Space Exploration
Mar 10, 2017
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Researchers are busy analysing some of the final data sent back from the Cassini spacecraft which has been in orbit around Saturn for more than 13 years until the end of its mission in September 2017.
Space Exploration
Jan 14, 2020
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Newly discovered layers of ice buried a mile beneath Mars' north pole are the remnants of ancient polar ice sheets and could be one of the largest water reservoirs on the planet, according to scientists at The University ...
Space Exploration
May 22, 2019
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Two research teams, using data from the European Space Agency's Mars Express orbiter, have recently published results suggesting that what were thought to be subsurface lakes on Mars may not really be lakes at all.
Planetary Sciences
Jul 3, 2021
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A colossal chess game of immense consequences is being fought in outer space, right now. On March 18 and April 22 2020, two rockets from SpaceX, owned by billionaire Elon Musk, each put 60 satellites into orbit. Those launches ...
Space Exploration
May 27, 2020
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290
The Earth's liquid molten outer core, composed mostly of iron and nickel, exerts an electromagnetic field extending from the north and south pole that protects the planet from harmful solar particle radiation.
Planetary Sciences
May 27, 2024
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New research suggests forces pulling on Earth's surface as the planet spins may trigger earthquakes and eruptions at volcanoes.
Earth Sciences
Dec 27, 2019
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Polarization (also polarisation) is a property of waves that describes the orientation of their oscillations. This article primarily covers the polarization of electromagnetic waves such as light, although other types of wave also exhibit polarization.
By convention, the polarization of light is described by specifying the direction of the wave's electric field. When light travels in free space, in most cases it propagates as a transverse wave—the polarization is perpendicular to the wave's direction of travel. In this case, the electric field may be oriented in a single direction (linear polarization), or it may rotate as the wave travels (circular or elliptical polarization). In the latter cases, the oscillations can rotate rightward or leftward in the direction of travel, and which of those two rotations is present in a wave is called the wave's chirality or handedness. In general the polarization of an electromagnetic (EM) wave is a complex issue. For instance in a waveguide such as an optical fiber, or for radially polarized beams in free space, the description of the wave's polarization is more complicated, as the fields can have longitudinal as well as transverse components. Such EM waves are either TM or hybrid modes.
For longitudinal waves such as sound waves in fluids, the direction of oscillation is by definition along the direction of travel, so there is no polarization. In a solid medium, however, sound waves can be transverse. In this case, the polarization is associated with the direction of the shear stress in the plane perpendicular to the propagation direction. This is important in seismology.
Polarization is significant in areas of science and technology dealing with wave propagation, such as optics, seismology, telecommunications and radar science. The polarization of light can be measured with a polarimeter.
This text uses material from Wikipedia, licensed under CC BY-SA