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cattywilde uploaded a new video
(3 weeks ago)
The roar of a rocket motor at a test range in Texas seems to herald America's intent to launch people back into space. Built by SpaceX of Hawthorne...
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The roar of a rocket motor at a test range in Texas seems to herald America's intent to launch people back into space. Built by SpaceX of Hawthorne, California, it's one of eight rockets that will be fitted into the conical flanks of the Dragon manned spacecraft. The capsule will allow for propulsive landings on Earth, the Moon or Mars as well as helping astronauts escape a fiery end if the rocket below them explodes.
The motors are hypergolic, meaning that they spontaneously ignite when their two fuels mix. Unlike a solid rocket motor that has to burn fully like a firework, this allows them to be switched on and off at will. Another advantage is that the fuels don't need to be cooled cryogenically.
In the event of an accident, however, volatile hypergolic fuels can be extremely dangerous. In his book Empire of the Clouds, author James Hamilton Paterson relates the grisly aftermath of a World War II rocket-powered airplane crash. "The Komet's fulminating rocket fuels would explode spontaneously when mixed in even minute quantities and on one hideous occasion had actually dissolved a pilot alive before rescuers could free him from his crashed aircraft," he writes.
Since those early days, aerospace engineers have learned a lot about hypergolic rocket motor safety and SpaceX will no doubt have the tanks well protected.
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cattywilde uploaded a new video
(1 month ago)
Hubble images are made, not born. Images must be woven together from the incoming data from the cameras, cleaned up and given colors that bring out...
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Hubble images are made, not born. Images must be woven together from the incoming data from the cameras, cleaned up and given colors that bring out features that eyes would otherwise miss. In this video from HubbleSite, online home of the Hubble Space Telescope, a Hubble-imaged galaxy comes together on the screen at super-fast speed.
NASA (c) Hubble (c)
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cattywilde uploaded a new video
(1 month ago)
How does air flow across a wing to generate lift? Since a wing's top surface is curved, it covers a greater distance compared to the flatter bottom...
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How does air flow across a wing to generate lift? Since a wing's top surface is curved, it covers a greater distance compared to the flatter bottom edge. A common explanation is that air moves faster over the top so that it reaches the end of the wing at the same time as the bottom flow, lowering the pressure on the top surface.
But this pressure explanation is just a myth, explains Holger Babinsky, professor of aerodynamics at the University of Cambridge. In an attempt to debunk the misconception, he filmed pulses of smoke flowing around an aerofoil. He pauses the motion in the video to show that the transit times over the top and bottom are not equal. The lines of smoke from the top have already surpassed the bottom ones once they reach the wing's tip.
Babinsky explains that, although lift is caused by a pressure change between the top and bottom surfaces, it's due to the change in the shape of the air flow, rather than its speed. "This is why a flat surface like a sail is able to cause lift," he says. "In this case, the distance on each side is the same but it is slightly curved when it's rigged, acting like an aerofoil."
New Scientist TV (c)
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cattywilde uploaded a new video
(1 month ago)
Time travel is more than just science fiction: it could be possible according to the laws of physics. However, building a time machine would likely...
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Time travel is more than just science fiction: it could be possible according to the laws of physics. However, building a time machine would likely be difficult and require technology that doesn't currently exist. In this animation, we look at how to build a time machine and the perplexing implications of such a feat.
For more about time travel, read our full-length article, which is part of our special on time: About time: Adventures in the fourth dimension. You can find out what exactly time is, if it really does fly when you're having fun and even check out the world's most accurate clock.
New Scientist TV (c)
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cattywilde uploaded a new video
(1 month ago)
Europe's Vista Telescope has revealed the nebula in stunning infrared detail bringing to life the visible imagery provided by their MPG/ESO 2.2-met...
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Europe's Vista Telescope has revealed the nebula in stunning infrared detail bringing to life the visible imagery provided by their MPG/ESO 2.2-metre telescope. Strands of cold nebular gas and a vibrant background of stars/galaxies can now be seen. Credit: ESO
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