Skip to main content

Home/ Advanced Concepts Team/ Group items tagged galaxy

Rss Feed Group items tagged

pacome delva

Galaxy clusters back general relativity - 0 views

  • The Copenhagen group discovered that the redshifts agreed with the predictions of both general relativity and f(R) gravity, the theory that tries to avoid dark energy. However, the error bars on the redshifts excluded MOND and TeVeS, the theories that try to avoid dark matter.
ESA ACT

Sensors for impossible stimuli may solve the stereo correspondence problem - Nature Neu... - 0 views

  •  
    The title could be from the Hitchhiker's Guide to the Galaxy: Sensors for impossible stimuli.
Kevin de Groote

Galaxy Zoo Mergers - 0 views

  •  
    Instead of classifying galaxies (image analysis), this new project asks the public to try to recreate collisions
Ma Ru

Dark Matter or Black Hole Propulsion? - 1 views

  •  
    Anyone out there still doing propulsion stuff? Two more papers just waiting to get busted... http://arxiv.org/abs/0908.1429v1 http://arxiv.org/abs/0908.1803
  • ...5 more comments...
  •  
    What an awful bunch of complete nonsense!!! But I don't think anybody wants to hear MY opinion on this...
  •  
    wow, is this serious at all...!?
  •  
    Are you joking?? The BH drive propses a BH with a lifetime of about an year, just 10^7 tons, peanuts!! Then you have to produce it, better not on Earth, so you do this in space, with a laser that produces an equivalent of 10^9 tons highly foucussed, even more peanuts!! Reasonable losses in the production process (probably 99,999%) are not yet taken into account. Engineering problems... :-) The DM drive is even better, they want to collect DM and compress it in a propulsion chamber. Very easy to collect and compress a gas of particles that traverse the Earth without any interaction. Perhaps if the walls of the chamber are made of artificial BHs?? Who knows??
  •  
    WRONG!!! we are all just WAITING for your opinion on this ....!!!
  •  
    well, yes my remark was ironic... I'm surprised they did a magazine on these concepts...! But the press is always waiting for sensational. They do not even wait for the work to be peer-reviewed now to make an article on it ! This is one of the bad sides of arxiv in my opinion. It's like a journalist that make an article with a copy-paste in wikipedia ! Anyway, this is of course complete bullsh..., and I would have laughed if I had read this in a sci-fi book... but in a "serious" article i'm crying... For the DM i do not agree with your remark Luzi. It's not dark energy they want to use. The DM is baryonic, it's dark just because it's cold so we don't see it by usual means. If you believe the in the standard model of cosmology, then the DM should be somewhere around the galaxies. But it's of course not uniformly distributed, so a DM engine would work (if at all...) only in the periphery of galaxies. It's already impossible to get there...
  •  
    One reply to Pacome, though the discussion exceeds by far the relevance of the topic already. Baryonic DM is strictly limited by cosomology, if one believes in these models, of course. Anyway, even though most DM is cold, we are constantly bombarded by some DM particles that come together with cosmic radiation, solar wind etc. etc. If DM easily interacted with normal matter, we would have found it long ago. In the paper they consider DM as neutralinos, which are neither baryonic nor strongly or electromagnetically interacting.
  •  
    well then I agree, how the fu.. they want to collect them !!!
jaihobah

Phys. Rev. Lett. 116, 031301 (2016) - Dark Matter Velocity Spectroscopy - 1 views

  •  
    'Whether mysterious high-energy photon emissions from our Galaxy come from dark matter or a more mundane source might be resolved by detecting their Doppler shifts along different lines-of-sight.'
Marcus Maertens

Breakthrough Initiatives - 2 views

  •  
    Machine learning yields detection of 72 new fast radio bursts from distant galaxy. SETI folks are getting excited.
jaihobah

Probing Planets in Extragalactic Galaxies Using Quasar Microlensing - 2 views

  •  
    Here, we show that quasar microlensing provides a means to probe extragalactic planets in the lens galaxy, by studying the microlensing properties of emission close to the event horizon of the supermassive black hole of the background quasar, using the current generation telescopes
Marcus Maertens

Giant black hole could upset galaxy evolution models - 0 views

  •  
    Its a big one!
johannessimon81

Indications for Gamma Ray Burst in our Galaxy - 1 views

  •  
    Abstract: In the last 3000 yr, one significant and rapid increase in the concentration of 14C in tree rings was observed; it corresponds to a gamma-ray energy input of 7x10^24 erg at Earth within up to one year in AD 774/5 (Miyake et al. 2012).
santecarloni

Amateur planet hunters find a world with a four star rating | Bad Astronomy | Discover ... - 4 views

  •  
    One more reason why we should be much more open about all these EO data we have .... The two citizen scientists, Kian Jek and Robert Gagliano, are listed as authors on the scientific paper recently published. I love this: the digital nature of these data make it far, far easier to analyze the science than it was in the past, and also easier to get the data out to people. Because of this, we have an explosive growth in these kinds of projects. Planet Hunters is great, but then so is Galaxy Zoo, Moon Mappers, Ice Hunters, and so many others. You can find several of these collected at the CosmoQuest website.
  •  
    Wiktor is also collecting these science games in the ACT-wiki. You should have a look at: http://sophia.estec.esa.int/actwiki/index.php/On-line_Games_4_Science
Luís F. Simões

Mapping Dark Matter Case Study - Kaggle - 3 views

  • Mapping Dark Matter competition to encourage the development of new algorithms that can measure the way dark matter causes tiny distortions in images of galaxies by changing their ellipticity, or how their shapes are stretched.
  •  
    Blog posts describing the approaches followed by the contestants that ranked 1st, 2nd and 3rd.
Dario Izzo

NASA Brings Earth Science 'Big Data' to the Cloud with Amazon Web Services | NASA - 3 views

  •  
    NASA answer to the big data hype
  •  
    "The service encompasses selected NASA satellite and global change data sets -- including temperature, precipitation, and forest cover -- and data processing tools from the NASA Earth Exchange (NEX)" Very good marketing move for just three types of selected data (MODIS, Landsat products) plus four model runs (past/projection) for the the four greenhouse gas emissions scenarios of the IPCC. It looks as if they are making data available to adress a targeted question (crowdsourcing of science, as Paul mentioned last time, this time climate evolution), not at all the "free scrolling of the user around the database" to pick up what he thinks useful, mode. There is already more rich libraries out there when it comes to climate (http://icdc.zmaw.de/) Maybe simpler approach is the way to go: make available the big data sets categorized by study topic (climate evolution, solar system science, galaxies etc.) and not by instrument or mission, which is more technical, so that the amateur user can identify his point of interest easily.
  •  
    They are taking a good leap forward with it, but it definitely requires a lot of post processing of the data. Actually it seems they downsample everything to workable chunks. But I guess the power is really in the availability of the data in combination with Amazon's cloud computing platform. Who knows what will come out of it if hundreds of people start interacting with it.
LeopoldS

A Galactic Origin for HE 0437-5439, The Hypervelocity Star Near the Large Magellanic Cloud - 1 views

  •  
    "we conclude that HE 0437-5439 was most likely a compact binary ejected by the Milky Way's central black hole" reminds me a bit of Francesco's proposal to get rid of Mercury for the stability of our solar system ... what was the proposal: "get rid of the sucker?"
LeopoldS

NASA - NASA's Fermi Telescope Finds Giant Structure in our Galaxy - 5 views

  •  
    wow ....
  • ...1 more comment...
  •  
    I guess that's the "exceptional object in our cosmic neighbourhood"...
  •  
    impressive! I'm sure it's connected to the black hole, at some point it must have been active. It shows how it's important to put all observations public !
  •  
    this is what they speculate ... the original image looks though much less impressive ...
pacome delva

Special relativity passes key test - 2 views

  • 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."
  •  
    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 ....
  •  
    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 !
pacome delva

Mysterious 'dark flow' at the edge of the universe - 1 views

  • Cosmologists have already observed two distinct effects caused by invisible entities in the universe: dark matter is known to affect the rotation of galaxies and dark energy seems to be causing the expansion of the universe to accelerate. Dark flow is the latest addition to this shadowy family.
  •  
    I think Lucas didn't know he would have such an impact in science with Star Wars...!
  •  
    do you think it could be the dark side of The Force?
  •  
    what else...?
pacome delva

Mapping Turbulence in the Solar Wind - 0 views

  • a team reports studying the turbulent flow of solar wind particles by monitoring the accompanying waves of magnetic field. The team used a cluster of satellites to measure the field in unprecedented spatial detail. They found that the waves aren't equally strong in all directions but are larger in certain preferred directions, as theorists had predicted. The observation will help astrophysicists better understand the consequences of the solar wind, including its effect on the transmission of cosmic rays, particles that arrive at Earth from elsewhere in our galaxy.
LeopoldS

Ample Dark Matter Ignites Starburst Galaxies | Wired Science | Wired.com - 1 views

  •  
    true?
  •  
    I think what these studies show (assuming that data and analysis are correct) is the fact that there is something fundamentally wrong about all this dark matter, dark energy dark whatever stuff. From this point of view I would say: nice result, go ahead!!
‹ Previous 21 - 40 of 49 Next ›
Showing 20 items per page