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pacome delva

Gravitational Theory Reproduces Superconducting Circuitry | Physical Review Focus - 0 views

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    Another candidate for analogue gravity ?
ESA ACT

Critical phenomena in microgravity: Past, present, and future - 0 views

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    This review provides an overview of the progress in using the low-gravity environment of space to explore critical phenomena and test modern theoretical predictions.
annaheffernan

Highly accurate quantum accelerometers - 5 views

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    Their accuracy is orders of magnitude better than what is currently being used, however at the moment, it sounds like quite a large setup -> they're working on getting it down to 1m^3 :o, still any gravity mapping instruments could benefit from these in the future.
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    Actually GPS is much more accurate, but as it doesnt work under water, the only alternative (without building an underwater GPS equivalent using probes) is to use cumulative accelerometer data. But as this is prone to drifting over time, quantum systems like this can help improving the accuracy significantly.
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    Very true :). I was thinking though when you want to remove 'noise' from any gravity mapping experiment, highly accurate accelerometers are required, like those used in GOCE.
Alexander Wittig

Small, cheap gravity gadget to peer underground - BBC News - 2 views

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    According to their Nature article, they can detect "a tunnel less than 1m across, buried 2m underground" just from its gravitational difference. Using a device that they predict could cost ~100 € in mass production. UK researchers have built a small device that measures tiny fluctuations in gravity, and could be used to monitor volcanoes or search for oil. Such gravimeters already exist but compared to this postage stamp-sized gadget, they are bulky and pricy.
jaihobah

A precise extragalactic test of General Relativity - 0 views

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    Einstein's theory of gravity, General Relativity (GR), has been tested precisely within the Solar System. However, it has been difficult to test GR on the scale of an individual galaxy. Collett et al. exploited a nearby gravitational lens system, in which light from a distant galaxy (the source) is bent by a foreground galaxy (the lens). Mass distribution in the lens was compared with the curvature of space-time around the lens, independently determined from the distorted image of the source. The result supports GR and eliminates some alternative theories of gravity.
Thijs Versloot

Particles defy gravity and float upstream - 3 views

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    Rogue tea leaves have led physicists to the discovery of a counter-intuitive phenomenon: Particles can float upstream in moving water.
santecarloni

The Higgs, Boltzmann Brains, and Monkeys Typing Hamlet | The Crux | Discover Magazine - 7 views

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    good luck with this....
  • ...3 more comments...
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    Nice article, actually! It summarizes in "human readable format" why and how too many cosmologists and string theorists just went bozo...
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    really ! this article should go for the ignobels ! http://arxiv.org/abs/0808.3778 I wonder which substance theorists are taking... I will avoid...! but really this is very preoccupating: "complex structures will occasionally emerge from the vacuum as quantum fluctuations, at a small but nonzero rate per unit spacetime volume. An intelligent observer, like a human, could be one such structure." Is this a new alternative to Darwinism...??? a support to creationism ?? How can a physicist can write such non-sense ?
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    and this is published in PRD !!!
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    In 1996 Sokal hoaxed sociologists with his famous nonsense text on political implications of quantum gravity. Can one play a similar game with "researchers" on Boltzmann brains, multiverses, string landscapes or similar? I doubt, this is just reality satire that can't be topped.
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    Poor Boltzmann ...
jcunha

Robot quadcopters could help scientists perform zero g experiments without the cost of ... - 1 views

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    Drones for microgravity.
Alexander Wittig

Proof of the Riemann Hypothesis utilizing the theory of Alternative Facts - 0 views

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    An excellent science coffee topic! This is a true breakthrough in pure mathematics with plentiful applications in the lesser sciences (such as theoretical physics). People tell me quantum gravity is already practically solved by this. Conway's powerful theory of Alternative Facts can render many difficult problems tractable. Here we demonstrate the power of AF to prove the Riemann Hypothesis, one of the most important unsolved problems in mathematics. We further suggest applications of AF to other challenging unsolved problems such as the zero-equals-one conjecture (which is also true) and the side-counting problem of the circle.
jaihobah

New Test of the Gravitational Inverse-Square Law at the Submillimeter Range with Dual M... - 1 views

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    "The experimental result shows that, at a 95% confidence level, the gravitational inverse-square law holds (|α|≤1) down to a length scale λ=59  μm"
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    Very cool experiment! Impressive. Newton sure got an epiphany...
jcunha

Europe plans giant billion-euro quantum technologies project - 0 views

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    After graphene and blue brain, the European Commission has quietly announced plans to launch a €1-billion Euro project to boost a raft of quantum technologies - from secure communication networks to ultra-precise gravity sensors and clocks.
jcunha

New method uses heat flow to levitate variety of objects - 1 views

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    Normally we associate levitation of objects to superconducting materials. Here a new technique is shown where levitation of a whole new range of materials is shown. "The large temperature gradient leads to a force that balances gravity and results in stable levitation," said Fung, the study's lead author. "We managed to quantify the thermophoretic force and found reasonable agreement with what is predicted by theory. This will allow us to explore the possibilities of levitating different types of objects." Paper at http://aip.scitation.org/doi/10.1063/1.4974489 New microgravity experiments possibility?
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    not really I fear .... "Typical sizes of the trapped particles are between 10 μm and 1 mm at a pressure between 1 and 10 Torr. The trapping stability is provided radially by the increasing temperature field and vertically by the transition from the free molecule to hydrodynamic behavior of thermophoresis as the particles ascend."
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    Might still be OK micro to mm sized experiments. The technique seems to be reliable and cheap enough to compete with other types of microgravity approaches - more research needed to define boundaries of course.
LeopoldS

GTOC problem announced! - 0 views

"This year's problem is the global mapping of Jupiter's Galilean satellites, Io, Europa, Ganymede, and Callisto, by means of close flybys. A trajectory must be designed for a low-thrust spacecraft ...

Mas ai

started by LeopoldS on 10 Sep 12 no follow-up yet
Thijs Versloot

Computer simulations of muscle-based biped locomotion (movie) - 3 views

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    Optimization of locomotion on a range of different bipeds with nice visualisation and funny movie (definitely watch at 3:25 !!) Also simulations at lower/higher gravity
Thijs Versloot

Bacterial growth in space - 0 views

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    According to the article it seems that the growth of biofilms in space (MIR, ISS) is continuing to be a challenge for any space missions. Hardly any information is present on what role gravity plays in their growth and development. Maybe detection is also one important aspect of this indeed (Tom?)
johannessimon81

Singing stars: a new way do characterize star properties - 0 views

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    Video shows how surface gravity and rotation rate of a star can be characterized from variations in its light
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