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Stephen Hawking: 'There are no black holes' : Nature News & Comment - 1 views

www.nature.com/...ere-are-no-black-holes-1.14583 PHY science space
shared by Marcus Maertens on 18 Feb 14 - No Cached
  • Marcus Maertens on 18 Feb 14
     
    Event Horizon - a modern myth?
  • dejanpetkow on 18 Feb 14
     
    GR is valid on large scales and is, therefore, a simplification of the unknown GUT. As such, the mathematical solutions obtained in GR are strictly speaking valid only within GR. Certainly, the solution called black hole is an extremely heavy object and at the same time extremely small - a point without geometrical extension. The latter is heavily in conflict with the validity range of the underlying theory and, hence, makes lots of people (including experts unlike me) question the concept of black holes despite the fact that something has been "observed" which fits into this concept. Regarding the movie: Event Horizon might be a myth but it emphasizes what Sante said in on of his presentations: Don't use a black hole for travelling, take the worm hole instead. The constructor of Event Horizon created a black hole not considering that the damn thing has no exit...where did he think the Event Horizon would end?
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The World's Fair 2014 - Isaac Asimov's predictions 40 years ago - 3 views

www.nytimes.com/...asi-v-fair.html history
shared by Thijs Versloot on 02 Jan 14 - No Cached
  • Thijs Versloot on 02 Jan 14
     
    saac Asimov's predictions of the year 2014 back in 1964.. Truly amazing to read how close his sharp mind turned out to be at that time (cold war, Yuri Gagarin just went into space and Fortran first appeared 7 years before). The last prediction also came true I think, however the solution was not psychiatry.. instead we invented Facebook, Twitter and Instagram
  • Thijs Versloot on 02 Jan 14
     
    Also, he predicted that solar power stations would power the places on earth where solar power nor fission (?) would be available... Not there yet
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Evolution of AI Interplanetary Trajectories Reaches Human-Competitive Levels - Slashdot - 4 views

science.slashdot.org/...aches-human-competitive-levels AI MAD GTOC PaGMO evolutionary computation trajectory optimization awards
shared by Luís F. Simões on 19 Jul 13 - No Cached
  • "It's not the Turing test just yet, but in one more domain, AI is becoming increasingly competitive with humans. This time around, it's in interplanetary trajectory optimization. From the European Space Agency comes the news that researchers from its Advanced Concepts Team have recently won the Gold 'Humies' award for their use of Evolutionary Algorithms to design a spacecraft's trajectory for exploring the Galilean moons of Jupiter (Io, Europa, Ganymede and Callisto). The problem addressed in the awarded article (PDF) was put forward by NASA/JPL in the latest edition of the Global Trajectory Optimization Competition. The team from ESA was able to automatically evolve a solution that outperforms all the entries submitted to the competition by human experts from across the world. Interestingly, as noted in the presentation to the award's jury (PDF), the team conducted their work on top of open-source tools (PaGMO / PyGMO and PyKEP)."
  • Luís F. Simões on 19 Jul 13
     
    We made it to Slashdot's frontpage !!! :)
  • Ma Ru on 23 Jul 13
     
    Congratulations, gentlemen!
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Did you know that Earth has a ring? - 3 views

www.wired.com/...project-west-ford space
shared by johannessimon81 on 13 Aug 13 - No Cached
  • johannessimon81 on 13 Aug 13
     
    Earth has had a ring of particles (similar to Saturn's) for a short period of time. And it is manmade.
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Hyperloop plan revealed by Elon Musk - 0 views

www.space.com/rloop-technology-revealed.html technology transport
shared by Thijs Versloot on 13 Aug 13 - No Cached
  • Thijs Versloot on 13 Aug 13
     
    More details in the linked pdf file.. a low pressurized tube with pods floating on air cushions together with EM propulsion and braking.. cool, but probably not going to be build any day soon
  • ...2 more comments...
  • H H on 13 Aug 13
     
    The point of this was that California is already planning to build a train line the would cost ten times more than this and be maybe one quarter of the speed. If the plan is actually feasible with the budget, this could very well have a chance...
  • Luzi Bergamin on 13 Aug 13
     
    A similar idea existed in Switzerland as well, it was called Swissmetro (http://en.wikipedia.org/wiki/Swissmetro) and intended to reach a ridiculously small top speed of about 500km/h. It had the same fate as Musk's idea will have soon: just a piece on the dump of history.
  • Thijs Versloot on 13 Aug 13
     
    It would be great indeed, but even though the cost of the high speed train is a factor 10x higher, the prototype nature and hence relatively lower TRL of this system will probably not have it favoured. Best chance is that he develops a working prototype, one that might not even transport humans at the moment and for short distances, then maybe the project can take off
  • H H on 13 Aug 13
     
    Actually, he was talking about a prototype: "I am somewhat tempted to at least make a demonstration prototype," Musk said in a conference call with reporters on Monday. "Perhaps I'll create a sub-scale version that's operating, and then hand it over to somebody else." "I think I'll probably end up doing that," he said. http://allthingsd.com/20130812/elon-musk-will-likely-build-his-own-hyperloop-prototype/
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Wanted: Volunteers for Yearlong Mock Mars Mission in Canadian Arctic - 2 views

www.space.com/mission-arctic-volunteers.html
shared by Beniamino Abis on 31 Oct 13 - No Cached
  • Beniamino Abis on 31 Oct 13
     
    Mars Society, which advocates for manned exploration of the Red Planet, has released its requirements for the six volunteers who will be expected to spend 12 months at the society's Flashline Mars Arctic Research Station on Canada's Devon Island, which is about 1,450 kilometers from the North Pole, beginning in July 2014. Crewmembers will spend most of their time doing science, studying things such as carbon release from the permafrost and human performance in extreme conditions. If they want to go outside their base, they'll have to wear a spacesuit. If something breaks, they're the ones who are going to have to fix it.
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Timelapse of a stellar explosion #IFLS - 2 views

www.iflscience.com/...lapse-stellar-explosion-hubble
shared by Thijs Versloot on 12 Jun 14 - No Cached
  • Thijs Versloot on 12 Jun 14
     
    An amazing video.. while science is still puzzled what actually happened
  • Ma Ru on 14 Jun 14
     
    There's one very simple explanation I can think of...
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Dolphin inspired radar #biomimicry - 2 views

phys.org/...-10-dolphins-radar-device.html tech bio radar
shared by Thijs Versloot on 23 Oct 13 - No Cached
  • Thijs Versloot on 23 Oct 13
     
    The device, like dolphins, sends out two pulses in quick succession to allow for a targeted search for semiconductor devices, cancelling any background "noise",
  • ...1 more comment...
  • Athanasia Nikolaou on 30 Oct 13
     
    and it sends out two pulses of opposite polarity, in succession, such that a semiconductor changes the negative to a positive one, amplifying the returning signal. Very interesting. Maybe we can combine different frequencies for identifying a single variable in earth observation. We already use more that one frequencies but for identifying one variable each.
  • Thijs Versloot on 31 Oct 13
     
    Could it be used to measure ocean acidification? I found a study that links sound wave propagation with ocean acidity. Maybe we are able to do such measurement from space even? "Their paper, "Unanticipated consequences of ocean acidification: A noisier ocean at lower pH," published last week in the journal Geophysical Research Letters, found that fossil fuels are turning up the ocean's volume. Since the beginning of the Industrial Revolution, the overall pH of the world's oceans has dropped by about 0.1 units, with more of the changes concentrated closer to the poles. The authors found that sound absorption has decreased by 15 percent in parts of the North Atlantic and by 10 percent throughout the Atlantic and Pacific"
  • Athanasia Nikolaou on 31 Oct 13
     
    The last time I asked an oceanographer for the use of acoustic waves, she said it is still a bit problematic method to take into account its data, but we were referring to measuring ocean circulation. It may be more conclusive for PH measurements, though. The truth is that there is a whole underwater network with pulse emmitters/receivers covering the North Atlantic basin, remnant infrastructure for spying activities in the WW2 and in the cold war, that stays unexploited. We should look more into this idea
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Alien star invaded the Solar System - 2 views

www.bbc.com/...science-environment-31519875 space science PHY
shared by Thijs Versloot on 23 Feb 15 - No Cached
  • Thijs Versloot on 23 Feb 15
     
    An alien star passed through our Solar System just 70,000 years ago, astronomers have discovered. No other star is known to have approached this close to us. An international team of researchers says it came five times closer than our current nearest neighbour - Proxima Centauri. Passing straight through the Oort Cloud region. This must have left some sort of mark maybe? A binary system of a red and brown dwarf (8% and 6% solar masses) so maybe not a too significant impact on trajectories in the Oort cloud?
  • Paul N on 24 Feb 15
     
    I read this earlier and thought it might be another one of those alien conspiracy stuff. Freaky stuff.
  • LeopoldS on 11 Mar 15
     
    what about taking a ride on one of these? - especially if they come with some companion planets? when is the next shuttle coming?
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Graphene sponge can absorb light and emit energetic electrons for breakthrough solar sa... - 1 views

nextbigfuture.com/...onge-can-absorb-light-and.html space technology
shared by aborgg on 04 Aug 15 - No Cached
  • aborgg on 04 Aug 15
     
    The unique structure and properties of graphene and the morphology of the bulk graphene material make it capable of not only absorbing light at various wavelengths but also emitting energetic electrons efficiently enough to drive the bulk material following Newtonian mechanics.
  • aborgg on 04 Aug 15
     
    Hard to believe this should actually work, but would be quite a breakthrough indeed. I wonder, since the material should build up a significant electric potential over time, thus, pulling back the ejected electrons. Well, the paper apparently is not peer-reviewed, and I found some rather critical comments in some forums. Let's see if the experiment will be verified by another research team in due course.
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Mission Idea Contest - 3 views

www.axelspace.com/...index.html mission mad fun science space prizes
shared by Juxi Leitner on 05 Jul 10 - Cached
LeopoldS and Joris _ liked it
  • Juxi Leitner on 05 Jul 10
     
    so any ideas from us here?! :)
  • ...1 more comment...
  • LeopoldS on 05 Jul 10
     
    fantastic - they launched it! he mentioned this already some time ago ... I really like it.
  • LeopoldS on 05 Jul 10
     
    btw: have been discussing something similar with Roger ... a bit less ambitious but still ...
  • Juxi Leitner on 06 Jul 10
     
    presentations from the related nanosatellite event http://www.nestra.jp/NS_sympo/information_e.html (DLR, SSTL and european unis were there but no ESA...)
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Run Wired, Run Deep: Subs May Finally Get Online | Danger Room | Wired.com - 1 views

www.wired.com/...1 INF technology space connectivity internet real-time communication
shared by Juxi Leitner on 05 Aug 10 - Cached
  • LeopoldS on 07 Aug 10
     
    strange that even if optical fibre this would not compromise the submarines location ...
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Is It Time To Revamp Systems Engineering? | AVIATION WEEK - 1 views

www.aviationweek.com/...story.jsp engineering
shared by Joris _ on 02 Nov 10 - No Cached
LeopoldS liked it
  • They both believe the systems engineering processes that have served the aerospace and defense community since pre-Apollo days are no longer adequate for the large and complex systems ­industry is now developing.
  • Joris _ on 02 Nov 10
     
    1) it has to actively work and produce a result that's what you intended 2) the design must be robust. 3) it should be efficient 4) it should minimize unintended consequences. "But we have to establish a formal, mathematically precise mechanism to measure complexity and adaptability . . . [where] adaptability means the system elements have sufficient margin, and can serve multiple purposes." "We need to break the paradigm of long cycles from design to product" some interesting questions....
  • ...1 more comment...
  • LeopoldS on 02 Nov 10
     
    indeed ... already hotly debated in CDF ... any suggestions in addition to what we already contributed to this (e.g. system level optimisation)
  • Joris _ on 03 Nov 10
     
    what is the outcome of the CDF study ? I think actually that optimisation is not at all the key point. As it is stressed in this news, it is robustness (points 2 and 4). This is something we should think about ...
  • Luzi Bergamin on 03 Nov 10
     
    SYSTEM OF SYSTEMS, SYSTEM OF SYSTEMS!!! :-D
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Special relativity passes key test - 2 views

physicsworld.com/...40834 phy quantum_gravity special_relativity gamma_ray_burst
shared by pacome delva on 15 Dec 09 - Cached
  • Granot and colleagues studied the radiation from a gamma-ray burst – associated with a highly energetic explosion in a distant galaxy – that was spotted by NASA's Fermi Gamma-ray Space Telescope on 10 May this year. They analysed the radiation at different wavelengths to see whether there were any signs that photons with different energies arrived at Fermi's detectors at different times.
  • According to Granot, these results "strongly disfavour" quantum-gravity theories in which the speed of light varies linearly with photon energy, which might include some variations of string theory or loop quantum gravity. "I would not use the term 'rule out'," he says, "as most models do not have exact predictions for the energy scale associated with this violation of Lorentz invariance. However, our observational requirement that such an energy scale would be well above the Planck energy makes such models unnatural."
  • Dario Izzo on 16 Dec 09
     
    essentially they made an experiment that does not prove or disprove anything -big deal-... what is the scientific value of "strongly disfavour"??? I also like the sentence "most models do not have exact predictions for the energy scale associated with this violation of Lorentz invariance" ... but if this is true WHAT IS THE POINT OF THE EXPERIMENT!!!! God, physics is in trouble ....
  • pacome delva on 17 Dec 09
     
    hum, null result experiments are not useless !!! there is always the hope of finding "something wrong", which would lead to a great discovery. For the state of theoretical physics (the "no exact predictions" quote), i totally agree that physics is in trouble... That's what happen when physicists don't care anymore about experiments...! All you can do now is drawing "nice"graph with upper bounds on some parameters of an all tunable weird theory !
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Evidence of life on Mars lurks beneath surface of meteorite, Nasa experts claim - Times... - 1 views

www.timesonline.co.uk/...article6934078.ece
shared by Christos Ampatzis on 27 Nov 09 - Cached
  • Christos Ampatzis on 27 Nov 09
     
    Is there life on Mars? - We should try to compress those images!
  • Francesco Biscani on 29 Nov 09
     
    "Is there life on Mars?" Yes, mostly on Saturday night...
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trois, deux, un, ... celebration of the 30 years of service - 1 views

www.happybirthday-ariane.eu ariane space esa technology
shared by Ma Ru on 14 Apr 10 - Cached
  • Ma Ru on 14 Apr 10
     
    Some time ago ESA posted two cool videos aimed to promote the Ariane programme. The website is the final product, I believe.
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Some *real* crowdsourcing by NASA - 1 views

www.planethunters.org space planet crowdsourcing NASA exoplanets software
shared by Ma Ru on 18 Dec 10 - No Cached
LeopoldS liked it
  • Ma Ru on 18 Dec 10
     
    For the time being the page does not load for me (overload?) but I've just read an article about it in the local news.
  • LeopoldS on 19 Dec 10
     
    loads fine for me ... and very nice layout - well done in general in my view
  • LeopoldS on 19 Dec 10
     
    This Zooniverse looks nice in general ... look also at the other projects: http://www.zooniverse.org/contact
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DailyTech - NASA Releases iPhone App - 2 views

www.dailytech.com/...article16613.htm
shared by Joris _ on 26 Oct 09 - Cached
  • The U.S. space agency has worked more diligently the past few years to better interact with the public.
  • Joris _ on 26 Oct 09
     
    what about ESA?
  • ...3 more comments...
  • LeopoldS on 26 Oct 09
     
    have already sent it as a suggestion to our com department ... btw: installed the app and its really well done!!
  • Francesco Biscani on 27 Oct 09
     
    God no, why give more taxpayers' money to the shittiest, greediest and most closed company out there??
  • LeopoldS on 27 Oct 09
     
    why "more" ... do they get any taxpayers money? answer to your question: because its the most efficient (and coolest) platform to convey your message to a larger audience with relatively little effort ... btw: just ordered a time capsule for home :-)
  • Francesco Biscani on 27 Oct 09
     
    I said "more" because we already gave them money in the form of Sophia and Atlas :) If we want to be consistent in promoting "open" efforts (open innovation, open source, open governance, etc.) we should avoid Apple like the plague. They are far far worse than Microsoft in terms of closedness, secrecy, shady market practices and vendor lock-in. Just google a bit and you will find lots of example of their behaviour.
  • nikolas smyrlakis on 28 Oct 09
     
    cant' really argue about the Apple practices, although I ve read some things. I think the NASA app is more like a news feed and nothing more. But that online crowdsourcing game we had in mind, now that would be cool in a mobile version - new mobiles also have accelerometers nowadays
1More

Asteroid blast reveals holes in Earth's defences - space - 26 October 2009 - New Scientist - 2 views

www.newscientist.com/...dn18046 asteroid
shared by Francesco Biscani on 28 Oct 09 - Cached
  • On 8 October an asteroid detonated high in the atmosphere above South Sulawesi, Indonesia, releasing about as much energy as 50,000 tons of TNT, according to a NASA estimate released on Friday. That's about three times more powerful than the atomic bomb that levelled Hiroshima, making it one of the largest asteroid explosions ever observed.
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