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Costa Rica has achieved a clean energy milestone by using 100 per cent renewable energy for a record 75 days in a row.
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Our species is still changing. What will become of it?
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How you and the world have changed since you were born
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Quoting from Archimedes being quoted in alternative versions, "Give me a place to stand and with a lever I will move the whole world."  

If we consider our skeletal structure as the lever, with the pull and push of muscle, that is indeed what our species had done in modifying the global environment to a great extent
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It looks this good to be a biological robot  
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Andrew Planet
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Check out these fun physics facts for kids. Learn about a wide range of cool topics such as gravity, electricity, light, sound and much more. Enjoy the world of science with their amazing physics facts.
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Just a note to you all, if any of you wish to make a post here on facts, any facts that you know about, please feel free to do so
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Light of Other Days

There’s a reason why the weak force is often described as “something something, radioactivity.” It was radioactivity that provided the first hint of the weak force, and it remains the most prominent physical phenomenon driven by the weak force. It all started back in the late 1800s, when Marie Curie and others began to study radioactive materials. These materials were odd because they released high energy rays seemingly in defiance of conservation of energy. By the early 1900s, Curie had shown that radioactive decay caused atoms to transmute from one type of element to another. The energy of these radioactive rays was provided by a transformation of mass into energy. As we observed the rates of radioactive materials, we found they decayed at a rate proportional to the amount of radioactive material. That is, radioactivity followed a half-life relation, where in a given period of time half the material would decay on average. By the 1930s we had a good understanding of how radioactive materials behaved, but no real idea as to why they exhibited that behavior.

The first step toward a theory of radioactive decay came from Enrico Fermi in 1933. Fermi’s model focused on beta decay, where a single neutron would decay into a proton and electron. One of the odd things about beta decay was that the energy of the emitted electrons varied. According to Einstein’s theory of special relativity (E = mc2), the energy of the electron should be the difference in energy between the neutron and proton, and should always be the same. To answer this mystery, Fermi proposed a new particle known as the neutrino. If a neutron emitted both an electron and neutrino when it decayed, then the neutrino would take some of the energy. The result of this model was known as Fermi’s golden rule, which seemed to explain how the half-life relation might occur.

Since the neutrino was chargeless (and presumed massless) it is tempting to imagine neutrinos playing a role in the weak interaction just as photons do in electromagnetism. It was soon clear that this wouldn’t work. As particle physics began to find a wide range of particles, their radioactive byproducts didn’t follow relations that neutrino mediated decay could explain. When the quark model was proposed, we found that rather than three elementary particles (electrons, protons, and neutrons), there were in fact twelve. These could be grouped into six quarks (up, down, charm, strange, top, and bottom), and six leptons (electron, muon, tau, and their corresponding neutrinos). Whatever this weak interaction was, it could cause heavier quarks to decay into lighter ones, and heavier leptons decay into lighter ones.

With the development of quantum electrodynamics for electromagnetism, and quantum chromodynamics for the strong interaction, we had an approach to consider. In both of these models there are charges (electric and color) with field quanta mediating their interactions (photons and gluons respectively). Even gravity can be approximated as mass “charges” interacting through gravitons. So what if quarks, leptons and neutrinos have a kind of “weak” charge that acts through a field quanta. This idea turns out to be right, but the details are complicated.

We can see some of this complexity in the type of field quanta the weak has. In electromagnetism, the photon is both massless and chargeless, and so can act over long distances. In the strong interaction, gluons are massless but have color charge. Because of this, a boson interaction causes a quark to change color. In radioactive decay (such as the beta decay of a neutron) particles change mass. This means the field quanta of the weak interaction must have mass. It turns out there are three field quanta. One is uncharged, and is called the Z. The other two are called W particles. One has a positive electric charge, and one has a negative electric charge.

You read that correctly. Two of the weak quanta have electric charge. They must have electric charge to in order to interact with quarks. For example, a neutron consists of three quarks (one up and two down). Since the up quark has a charge of +2/3 (where -1 is an electron charge) and the down quark a charge of -1/3, the three add up to 0. A proton, on the other hand consists of two up and one down, with a charge of +1. In order for a neutron to decay into a proton a down quark must become an up quark, and thus gain a charge of +1. The charged W quanta lets that happen. Just as a gluon interaction allows quarks to change “color,” the W interactions allow quarks to change mass and charge (and thus type). The weak interaction is, quite literally, radioactive decay. Since the weak quanta have mass, they can only interact over short distances (just like Yukawa’s pion interaction between protons and neutrons). This is why radioactive decay occurs within atomic nuclei, but not between atoms in a molecule.

The fact that weak interactions can involve electric charge would seem to hint at some connection between the weak and electromagnetic forces. In 1968  Sheldon Glashow, Abdus Salam and Steven Weinberg showed just how they were connected by introducing the electroweak model. Just as electromagnetism unified electricity and magnetism as a single theory, the electroweak model unified electromagnetism with the weak, showing that the Ws, Z and photon are all related as electroweak quanta. This unity only becomes significant at very high temperatures, such as during the early moments of the big bang. Its success has led to work toward unifying the electroweak and strong into a grand unified theory (GUT), with dreams of even uniting gravity in a theory of everything (TOE). Whether or not that’s possible is yet to be determined, but for now we understand the weak interaction as the foundation of radioactive decay.

We normally think of radiation as being harmful, and sometimes it is. But we also wouldn’t be here without it. Our Sun is powered by nuclear fusion, just like all other stars. While the fusing of lighter nuclei into heavier nuclei requires the strong force to hold them together, fusion sometimes need a little help. In “small” stars like our Sun, the first step in the fusion chain is when two protons come together. The strong force can’t hold two protons together easily, so usually two protons come together for a brief moment only to fly apart again. But sometimes when two protons are together, a W quanta can interact with them, and one proton decays into a neutron, positron and neutrino. The strong force can hold together a proton and neutron (which we call deuterium), and collisions with deuterium eventually lead to helium. Without that simple weak interaction, smaller stars (the kind that burn for billions of years) couldn’t fuse hydrogen to helium. Without the weak force, there would be no Sun-like stars for Earth-like planets.

We notice gravity and electromagnetism in our daily lives, but it is the strong force that built the atoms in our bodies, and it is the weak force that has allowed the Sun to nurture life on Earth for billions of years.
The weak force is what causes radioactive decay. It's also what has made life on Earth possible.
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Andrew Planet
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Dance of the Hag

On the face of it both electricity and magnetism are remarkably similar to gravity. Just as two masses are attracted to each other by an inverse square force, the force between two charged objects, or two poles of a magnet are also inverse square. The difference is that gravity is always attractive, whereas electricity and magnetism can be either attractive or repulsive. For example, two positive charges will push away from each other, while a positive and negative charge will pull toward each other. As with gravity, electricity and magnetism raised the question of action-at-a-distance. How does one charge “know” to be pushed or pulled by the other charge? How do they interact across the empty space between them? The answer to that question came from James Clerk Maxwell.

Maxwell’s breakthrough was to change the way we thought electromagnetic forces. His idea was that each charge must reach out to each other with some kind of energy. That is, a charge is surrounded by a field of electricity, a field that other charges can detect. Charges possess electric fields, and charges interact with the electric fields of other charges. The same must be true of magnets. Magnets possess magnetic fields, and interact with magnetic fields. Maxwell’s model was not just a description of the force between charges and magnets, but a also description of the electric and magnetic fields themselves. With that change of view, Maxwell found the connection between electricity and magnetism. They were connected by their fields. A moving electric field creates a magnetic field, and a moving magnetic field creates an electric field. Not only are the two connected, but one type of field can create the other. Maxwell had created a single, unified description of electricity and magnetism. He had united two different forces into a single unified force, which we now call electromagnetism.

Maxwell’s theory not only revolutionized physics, it gave astrophysics the tools to finally understand some of the complex behavior of interstellar space. By the mid-1900s Maxwell’s equations were combined with the Navier-Stokes equations describing fluids to create magnetohydrodynamics (MHD). Using MHD we could finally begin to model the behavior of plasma within magnetic fields, which is central to our understanding of everything from the Sun to the formation of stars and planets. As our computational powers grew, we were able to create simulations of protostars and young planets. Although there are still many unanswered questions, we now know that the dance of plasma and electromagnetism plays a crucial role in the formation of stars and planets.

While Maxwell’s electromagnetism is an incredibly powerful theory, it is a classical model just like Newton’s gravity and general relativity. But unlike gravity, electromagnetism could be combined with quantum theory to create a fully quantum model known as quantum electrodynamics (QED). A central idea of quantum theory is a duality between particle-like and wave-like (or field-like) behavior. Just has electrons and protons can interact as fields, the electromagnetic field can interact as particle-like quanta we call photons. In QED, charges and a electromagnetic fields are described as interactions of quanta. This is most famously done through Richard Feynman’s figure-based approach now known as Feynman diagrams.

Feynman diagrams are often mis-understood to represent what is actually happening when charges interact. For example, two electrons approach each other, exchange a photon, and then move away from each other. Or the idea that virtual particles can pop in and out of existence in real time. While the diagrams are easy to understand as particle interactions, they are still quanta, and still subject to quantum theory. How they are actually used in QED is to calculate all the possible ways that charges could interact through the electromagnetic field in order to determine the probability of a certain outcome. Treating all these possibilities as happening in real time is like arguing that five apples on a table become real one at a time as you count them.

QED has become the most accurate physical model we’ve devised so far, but this theoretical power comes at the cost of losing the intuitive concept of a force. Feynman’s interactions can be used to calculate the force between charges, just as Einstein’s spacetime curvature can be used to calculate the force between masses. But QED also allows for interactions that aren’t forces. An electron can emit a photon in order to change its direction, and an electron and positron can interact to produce a pair of photons. In QED matter can become energy and energy can be come matter.

What started as a simple force has become a fairy dance of charge and light. Through this dance we left the classical world and moved forward in search of the strong and the weak.

Tomorrow: The strong force answered the question of how positive charges could be bound in the nuclei of atoms, and allowed us to understand the origin of matter itself.
Electromagnetism can produce a force between charges or magnets, but it is much more than a simple force.
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About this community

There exists a wide variety of people whose personal belief system is based purely on experimentally verifiable facts. These may be atheists or people who believe in a God so I wish to find a common ground for all of them in this community. This is work in progress

Andrew Planet
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The Types of Intelligence

In 1983 Howard Gardener described 9 types of intelligence:

1: Logical-mathematical
2: Linguistic
3: Bodily kinesthetic
4: Musical
5: Naturalist
6: Interpersonal
7: Intra-personal
8: Spacial
9: Existential

What other scientists thought were just soft-skills, such as interpersonal skills, Gardener realized were types of intelligence. It makes sense. Just as being a math whiz gives you the ability to understand the world, so does being “people smart” give you the same ability, just from a different perspective. Not knowing math you may not calculate the rate at which the universe is expanding, but you are likely to have the skills to find the right person who will.

Even 20 years after Gardener’s book came out, there is still a debate whether talents other than math and language are indeed types of intelligence or just skills. What do you think?

#psychology #productivity #infographic #intelligence #talent #mind

Via: http://fundersandfounders.com
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This Women’s History Month, Science Friday celebrates some of the unsung heroines of science.
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 I find this very odd, very much the doubter here. A pendulum depends of gravity for the the swing frequency and I find it difficult to find a relationship between the pendulum and the gravitational pull of the very distant Moon and the Sun.

Now if for some reason the gravitational alignment of the Moon and the Sun augments its effect with the Earth, including its surface, and its own gravity, that is beyond my ability to sum up. You’d think that any anomalous result would have to do with gravitational alignment because that is indeed happening as in the additional pull of a solar tide added to the lunar tide.

Would there be a difference in anomalous results depending on whether it was an eclipse during when the Earth is around closest or most distant from the moon or Sun or both? After writing the above I found this following article on solar tide

http://www.dailymail.co.uk/travel/travel_news/article-3005352/Thousands-flock-Mont-Saint-Michel-France-witness-tide-century.html

http://en.wikipedia.org/wiki/Lunar_distance_%28astronomy%29
The Allais effect is an anomalous result seen in pendulums during a total eclipse. Whether it's real or due to careless experiments is still debated.
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The Mapping of Pluto Begins Today
When New Horizons flies past Pluto in July, we will see a new, alien landscape in stark detail. At that point, we will have a lot to talk about. The only way we can talk about it is if those features, whatever they turn out to be, have names.
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Hangout Schedules Calendar, Index & Updates - March 2015
Calendar: goo.gl/YodHQc | Index: goo.gl/tivkgD | House Rules: goo.gl/3z2kfi 
CosmoQuest Hangoutathon 2015: bit.ly/CQHangout2015goo.gl/krfLlC
This post contains an overview of the hangouts we keep track on in the calendar and the index page on my blog. Links to previous versions of this post are at the bottom. We willl now use the comments of this post mainly as a changelog for the calendar and for other hangout-related updates - if you know about an interesting hangout, feel free to comment here or put the event in the Hangouts & Podcasts section!

The CosmoQuest Hangoutathon 2015
The annual live hangout fundraiser for +CosmoQuest, scheduled for 8am on April 25 until 8pm on April 26 Pacific Time. More details will follow as they come available, but you can already donate NOW by going to bit.ly/CQHangout2015 ! See also +Pamela L. Gay's original community post at goo.gl/krfLlC for further information.

Astronomy Cast Live
Live recording of the podcast with +Pamela L. Gay​​​ and +Fraser Cain​​​.  
Broadcast usually Mondays at 20:00 UTC.
See +Astronomy Cast​​​ and +CosmoQuest​​​ for announcements and updates. Audio Podcast available at www.astronomycast.com .
Youtube Archive Playlist: goo.gl/RCT9DM

Weekly Space Hangout
Weekly space news show hosted by +Fraser Cain​​​ with a rotating crew of guest journalists. Broadcast usually Fridays at 20:00 UTC.
See +CosmoQuest​​​ for details and announcements.
Youtube Archive Playlist: goo.gl/Kh1VvI

Learning Space
Weekly show about science and astronomy in education, hosted by +Nicole Gugliucci​​​ and +Georgia Bracey​​​. Usually broadcast Wednesday at 19:00 UTC.
Schedule: goo.gl/GBjO7a
See +Learning Space​​​ and +CosmoQuest​​​ for details and announcements.
Youtube Archive Playlist: goo.gl/PYCmsR

Inspiring Science Education Hangouts
Bi-weekly online training series about astronomy and physics, hosted by +Pamela L. Gay​​​ in collaboration with the +Galileo Teacher Training Program​​​. Usually broadcast every second Wednesday at 18:00 UTC.
See +Inspiring Science Education Hangouts​​​ for details and announcements.
Youtube Archive Playlist: goo.gl/3O7TFZ

Virtual Star Party
Semi-regular hangouts with live telescope views.
On hiatus at the moment because of weather and time constraints.
See +Virtual Star Party​​​ for updates and announcements.
Youtube Archive Playlist: goo.gl/h5YGhP

Hubble Hangouts
Weekly hangouts hosted by +Tony Darnell​​​ and +Scott Lewis​​​. 
Broadcast usually Wednesday or Thursday between 19-21:00 UTC
See +Hubble Space Telescope​​​ for updates and announcements
Youtube Archive Playlist: goo.gl/3JnINR

Know the Cosmos Hangouts
Semi-regular hangouts with +Katie Mack​​​ & +Scott Lewis​​​. 
Current series: Conversations with an Astrophysicist
See +KnowTheCosmos​ for updates and announcements.
Youtube Archive Playlist: goo.gl/iTrOMu

Dawn EPO / CosmoQuest Hangouts
Semi-regular hangouts with the Dawn Mission EPO team in collaboration with CosmoQuest.
See +Dawn Mission Education and Communications (E/C)​​​ for updates and announcements.
Youtube Archive Playlist: goo.gl/C2yjT0

Google Lunar XPrize Hangouts
Semi-regular hangouts with the Google Lunar XPrize contestants, hosted by +Pamela L. Gay​​​ in collaboration with CosmoQuest.
See +Google Lunar X PRIZE​​​ for updates and announcements.
Youtube Archive Playlist: goo.gl/ykCTKH

Astronomers Without Borders Hangouts
Semi-regular hangouts with special guests, hosted by +Mike Simmons​. See +Astronomers Without Borders​ for updates and announcements. 
Youtube Archive Playlist: goo.gl/MMdJQj

Previous versions of this post are located here:
» goo.gl/eUjsM8 - July-September 2014
» goo.gl/yN3Lve - September-October 2014
» goo.gl/F7crLo - October-December 2014
» goo.gl/3sHx1I - January-February 2015
» goo.gl/pfNG3j - March 2015 (replaced with Hangoutathon version)
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Here is a selection of interesting statistics and snippets of physics information. Most are in some way related to the topics discussed here; some are a little off-topic, but nevertheless fascinating.They are grouped them together under general question headings.
The Physics of the Universe - A Few Random Facts
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@ Science Alert  "Ever wondered what radiation looks like? If you have, I bet you didn’t think it would look as cool as this. This is a small piece of uranium mineral sitting in a cloud chamber, which means you can see the process of decay and radiation emission.

So, what’s a cloud chamber? It’s a sealed glass container cooled to -40°C, topped with a layer of liquid alcohol. According to Cloudylabs on YouTube, who made the video above, vapour emitted from the alcohol fills the container below, and most of it condenses on the glass surface, but some of it will remain as a vapour above the cold condenser. 

"This creates a layer of unstable sursaturated vapour which can condense at any moment,” says Cloudylabs. "When a charged particle crosses this vapour, it can knock electrons off the molecules forming ions. It causes the unstable alcohol vapour to condense around ions left behind by the travelling ionising particle. The path of the particle in the matter is then revealed by a track composed of thousands droplets of alcohol.”

Using this equipment, you can visualise any charged particle, including alphas, electrons, positrons, protons, nuclear charged fragments, and muons, and their tracks will look different, depending on how fast they travel, how much mass they have, and their charge. 

Cloudylabs explains what you can see in the video above:

"This video shows the Cloudylabs's cloud chamber running for approx. 50 min with an Uranium mineral. After 40 min, there is not enough alcohol to make newer trails. With time, the alcohol [will] condense on the mineral. The small thickness of liquid alcohol on the mineral is enough to absorb a part of the energy of the alpha particles (their ranges in air for 5 MeV is 3-4 cm, but in water, it's 15 micrometres), so with time, the trails are shorter than in [the] beginning. It's preferable to make such experience during 10 minutes to have longer alpha track."

Esther Inglis-Arkell over at io9 has a really great rundown of how you can actually do something similar to this yourself using nothing by party supplies. And nope, no uranium required."

http://www.sciencealert.com/watch-uranium-emits-radiation-inside-cloud-chamber
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JPL will stream a news briefing live online to discuss the March 6 arrival of NASA's Dawn spacecraft at the dwarf planet Ceres -- the largest unexplored world of the inner solar system.
Dawn Ceres Arrival
Mon, March 2, 12:00 PM
http://youtu.be/sJr-pctUYdw

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