Milky Way's missing satellite galaxies: Interactive dark matter

The simulated distribution of DM in a Milky Way-like galaxies for standard, non-interacting dark matter (top left), warm dark matter (top right) and the new dark matter model that interacts with the photon background (bottom) are shown. 

Smaller structures are erased up to the point where, in the most extreme model (bottom right), the galaxy is completely sterilized. 

Credit: Credit: Durham University

Scientists believe they have found a way to explain why there are not as many galaxies orbiting the Milky Way as expected.

Computer simulations of the formation of our galaxy suggest that there should be many more, smaller galaxies around the Milky Way than are observed through telescopes.

This has thrown doubt on the generally accepted theory of cold dark matter, a substance that scientists predict should allow for more galaxy formation around the Milky Way than is seen.

Now cosmologists and particle physicists at the Institute for Computational Cosmology (ICC) and the Institute for Particle Physics Phenomenology (IPPP), at Durham University, working with colleagues at LAPTh College & University in France, think they have found a potential solution to the problem.

Writing in the journal Monthly Notices of the Royal Astronomical Society (MNRAS), the scientists suggest that dark matter particles, as well as feeling the force of gravity, could have interacted with photons and neutrinos in the young Universe, causing the dark matter to scatter.

Scientists think clumps of dark matter, or halos, that emerged from the early Universe, trapped the intergalactic gas needed to form stars and galaxies.

Scattering the dark matter particles wipes out the structures that can trap gas, stopping more galaxies from forming around the Milky Way and reducing the number that should exist.

Two models of the dark matter distribution in the halo of a galaxy like the Milky Way, separated by the white line are shown. 

The colours represent the density of dark matter, with red indicating high-density and blue indicating low-density. 

On the left is a simulation of how non-interacting cold dark matter produces an abundance of smaller satellite galaxies. 

On the right the simulation shows the situation when the interaction of dark matter with other particles reduces the number of satellite galaxies we expect to observe around the Milky Way. 

Credit: Durham University

Lead author Dr Celine Boehm, in the Institute for Particle Physics Phenomenology, at, Durham University, said: "We don't know how strong these interactions should be, so this is where our simulations come in.

"By tuning the strength of the scattering of particles, we change the number of small galaxies, which lets us learn more about the physics of dark matter and how it might interact with other particles in the Universe.

"This is an example of how a cosmological measurement, in this case the number of galaxies orbiting the Milky Way, is affected by the microscopic scales of particle physics."

There are several theories about why there are not more galaxies orbiting the Milky Way, which include the idea that heat from the Universe's first stars sterilised the gas needed to form stars.

The researchers say their current findings offer an alternative theory and could provide a novel technique to probe interactions between other particles and cold dark matter.

Co-author Professor Carlton Baugh, in the Institute for Computational Cosmology, at Durham University, said: "Astronomers have long since reached the conclusion that most of the matter in the Universe consists of elementary particles known as dark matter.

"This model can explain how most of the Universe looks, except in our own backyard where it fails miserably.

"The model predicts that there should be many more small satellite galaxies around our Milky Way than we can observe.

"However, by using computer simulations to allow the dark matter to become a little more interactive with the rest of the material in the Universe, such as photons, we can give our cosmic neighbourhood a makeover and we see a remarkable reduction in the number of galaxies around us than originally thought."

The calculations were carried out using the COSMA supercomputer at Durham University, which is part of the UK-wide DiRAC super-computing framework.

More information: Monthly Notices of the Royal Astronomical Society , mnrasl.oxfordjournals.org/look… 0.1093/mnrasl/slu115

NASA Saturn Cassini Solstice Mission - Interactive

NASA has released some pretty amazing audio recordings of sounds from the moons of Saturn.

The weirdest thing about them is that they actually sound like a Theremin with it's warbles and whoosh sounds, like a ‘50s movies about space.

Life Robotic: Nextage Industrial Humanoid - YouTube

Robots aren’t new to product assembly, but these bots show a real improvement over the typical industrial machine. Nextage bots work in perfect coordination to complete tasks (in this case, they’re putting together a simple electronic sign).

Each is aware of its surroundings; if one robot is moved, it can orient itself and return to work. The developers, AIST and Kwada of Japan, made the robots look and move like humans so they can easily fit into our work environments. The question, of course, is if they’re skilled enough to actually replace the human workforce in factories.

Interactive Mirror technology: New York Times

Information is everywhere — in the world, in your home, everywhere. In today’s pair of videos from my visit to The New York Times Co.’s R&D Lab, Brian House, The Times Co.’s Creative Technologist for R&D, demonstrates the Lab’s, reflection of that idea — in the form of a data-bearing mirror.

The device (working name: “the magic mirror”) uses Microsoft’s Kinect motion-sensing technology to read physical cues from its user; it uses voice recognition technology to detect verbal cues. (In the videos, you’ll hear House talk to the mirror, Snow White-style.) The mirror also uses the the Times’ powerful APIs to serve up information on-demand.

The device, within its notional home, would replace the standard bathroom mirror. And like the R&D Lab’s screen-topped table, it’s all about bringing a new kind of intimacy to the news experience. You can use it, say, to browse Times headlines, or watch Times videos, while you’re brushing your teeth.


You can use it to schedule events on your personal calendar, or to shop online, or to exchange messages — from the classic “buy milk” on up — with other members of your household.

While the mirror is capable of serving (relatively) traditional forms of content — individual articles, videos, etc. — via its screen functionality, even more striking is its experimentation with information that has, directly, very little to do with the Times itself.

In exploring the realms of health and commerce alongside more standard editorial content, the Times Co. is hinting at the products we might see when news organizations expand their scope beyond the news itself.

Essentially, the mirror fuses news — and, in this case, a highly branded, New York Times experience of the news — with all the other forms of data that we encounter in our daily lives. Again, the “information shadow” idea.

By building a device that is both a screen and a mirror, the R&D Lab can experiment with the ways to combine the personal and the informational in ways that (it hopes!) aren’t intrusive, but rather helpful and, in that, welcome.

This is The New York Times Company acting not just as a curator of information about the wider world, but also as a curator of the information that punctuates, and complicates, and in some sense defines its customers’ personal lives.

Interactive 3D Model of Solar System

Click on the Picture to eneter the Solar System

Welcome to Solar System Scope space traveller, SSS means Astronomy for Everybody.

Whether you are a student, astronomy fan or an accidental browser, you are most welcome to play with our user-friendly application. 

It's full of space-art graphics, has easy-to-use interface with various settings and offers interesting information.

SSS will illustrate you real-time celestial positions with planets and constellations moving over the night sky.

But I can see you're not just a passive spectator - and that's good, because you can actively change parameters for a better understanding of happenings in our Solar System and the Universe.

Iran's Hidden Nuclear Facility - Interactive MAP Feature - NYTimes.com

Iran?s Hidden Nuclear Facility - Interactive Feature - NYTimes.com

Iran's Hidden Nuclear Facility

Images show the details of a hidden facility in Iran that experts say is the nuclear site recently disclosed by the Obama administration. Information about the plant is from an analysis by IHS Jane's.

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