Category: Physics

An astonishing space mission to visit our nearest star system and find out if alien life exists has been launched by Professor Stephen Hawking.

Despite being visible in the night sky without a telescope, Alpha Centauri is 25 trillion miles away (4.3 light years) and would take around 30,000 years to reach with current technology.

However Professor Hawking has joined forces with Russian billionaire Yuri Milner and Facebook’s Mark Zuckerberg, to develop technology which would allow a spacecraft to reach the star system in just 20 years.

Once there, a probe would sweep past the planets hunting for signs of advanced alien civilisations.

Earth-like planets have already been detected around the three stars of Alpha Centauri and scientists are hopeful that some may by located in the ‘Goldilocks Zone’ – an area where it is neither too hot, nor cold, for life to thrive.

Launching the initial $100 million phase of the ‘Starshot’ mission at the One World Observatory in New York City, Prof Hawking said: “There are no greater heights to aspire to than the stars.

“What makes human beings unique? There are many theories. Some say it is language or tools, others say it is logical reasoning. They obviously haven’t met many humans.

“I believe what makes us unique is transcending our limits. Gravity pins us to the ground, but I just flew to America. I lost my voice but I can still speak. How do we transcend these limits? With our minds and our machines.

“The limit that confronts us now is the great void between us and the stars but now we can transcend it, with light beams and light sails and the lightest spacecraft ever built we can launch a mission to Alpha Centauri within a generation.”

Source: Professor Stephen Hawking announces mission to Alpha Centauri

Does the man dream that he is a butterfly or is the butterfly dreaming that he is a man: Can we really tell our dreams from reality?

This question, asked by a netizen on China’s most popular microblog site Weibo on Thursday, was directed at the official account of world-renowned British theoretical physicist Stephen Hawking.

Hawking replied, “We don’t or perhaps can’t.”

The question was discussed by influential ancient Chinese philosopher Zhuangzi, who was known for his philosophy of skepticism. It was Zhuangzi who had dreamed of being a butterfly, or perhaps it was the butterfly who dreamed he was Zhuangzi. Either way, it has been the starting point for discussions on reality, self, illusions and more for over 2,000 years.

In his fourth posting on the microblog, Hawking, who has 3.6 million followers on Weibo – more than the population of Wales – selected the question from comments left on his previous updates.

“Zhuangzi dreamed of being a butterfly – perhaps because he was a man who loved freedom,” he said.

Hawking said, in his case, he might dream of the universe and wonder if the universe dreamed of him, “but we humans just don’t and perhaps can’t know if we are living in our dreams or reality, at least not until we start to understand more about consciousness and the universe.”

The era in which Zhuangzi lived is considered by many Chinese thinkers to be a time “when a hundred schools of thought contended.”

Chinese philosophers argue that Dao (the Way), from which Daoism gets its name, is the most indefinable of them all.

The Way of the universe is change: Night into day, joy into sorrow, life into death. Nothing is fixed, nothing definable. Moreover, everything is connected. No one knows where the Way leads.

Over 40,000 web users had commented on or forwarded the post within 24 hours of it being published. One follower said Hawking’s answer was “a historic conversation.”

Since Hawking opened his Sina Weibo account on April 12, his four posts have been forwarded 572,000 times, received 620,000 comments and been liked by over two million users.

In a previous post, Hawking introduced his Chinese followers to his latest project – Alpha Centauri, an astonishing space mission to our nearest star system.

Hawking said that the project, a collaboration with Russian venture capitalist Yuri Milner and Facebook CEO Mark Zuckerberg, would revolutionize space travel as it would use tiny nano-spacecraft able to travel fast enough to relay information to humans within a life time. It means humans would learn more about the galaxy, and ultimately themselves.

Source: Hawking answers ancient Chinese philosophical question|Europe|

Most believers in the healing qualities of radiation are suffering from a chronic inflammatory disease: arthritis, asthma or psoriasis, for example. The gas, they argue, alleviates their problems for months, which is why they lay in bubbling radon water offered by some healing spas. In Bad Kreuznach, in the German state of Rhineland-Palatinate, brave spa guests even trek into the tunnels of an abandoned mercury mine, attracted by the radon-filled air in the mountain. Are they crazy?

As has now become clear, these people are right: Radioactivity is good for them.

These are the initial findings of an ongoing large-scale trial conducted by researchers from four German institutes. The leader is radiobiologist Claudia Fournier, from the Helmholtz Center for Heavy Ion Research in Darmstadt.

Hundreds of patients in the spa resort of Bad Steven, in Upper Franconia, allowed themselves to be thoroughly examined for the study. The researchers found that after a series of radon baths, the blood of the test subjects had fewer signs of inflammation. Their immune defense, which is often in overdrive due to their illnesses, also seemed to have calmed down.

Accompanying experiments on arthritic mice delivered a further surprise. After the experiment, bone loss, which typically goes along with joint inflammation, was also reduced.

Still, radon is in no way harmless and may cause lung cancer in higher doses. How can this same gas have beneficial effects, mitigate inflammation and strengthen bones?

Its advantages for humans and mice have not yet been confirmed beyond all doubt, and further experiments are necessary. But biologist Fournier is reasonably sure that her results point in a new direction: “In low doses, radiation works differently than we had expected,” she says.

Source: Chernobyl Hints Radiation May Be Less Dangerous than Thought – SPIEGEL ONLINE

Cosmic rays are atom fragments that rain down on the Earth from outside of the solar system. They blaze at the speed of light and have been blamed for electronics problems in satellites and other machinery.

First discovered in 1912, many things about cosmic rays remain a mystery more than a century later. One prime example is exactly where they are coming from. Most scientists suspect their origins are related to supernovas (star explosions), but the challenge is that cosmic ray origins appear uniform when you look across the entire sky.

While cosmic rays were only discovered in the 1900s, scientists knew something mysterious was going on as early as the 1780s. That’s when French physicist Charles-Augustin de Coulomb — best known for having a unit of electrical charge named after him — observed an electrically charged sphere suddenly and mysteriously not being charged any more.

At the time, air was thought to be an insulator and not an electric conductor. With more work, however, scientists discovered that air can conduct electricity if its molecules are charged or ionized. This would most commonly happen when the molecules interact with charged particles or X-rays.

But where these charged particles came from was a mystery; even attempts to block the charge with large amounts of lead were coming up empty. On Aug. 7, 1912, physicist Victor Hess flew a high-altitude balloon to 17,400 feet (5,300 meters). He discovered three times more ionizing radiation there than on the ground, which meant the radiation had to be coming from outer space.

But tracing cosmic ray “origin stories” took more than a century. In 2013, NASA’s Fermi Gamma-ray Space Telescope released results from observing two supernova remnants in the Milky Way: IC 433 and W44.

Among the products of these star explosions are gamma-ray photons, which (unlike cosmic rays) are not affected by magnetic fields. The gamma rays studied had the same energy signature as subatomic particles called neutral pions. Pions are produced when protons get stuck in a magnetic field inside the shockwave of the supernova and crash into each other.

In other words, the matching energy signatures showed that protons could move at fast enough speeds within supernovas to create cosmic rays.

– See more at:

Source: What Are Cosmic Rays?

The concept is known as a “parallel universe,” and is a facet of the astronomical theory of the multiverse. There actually is quite a bit of evidence out there for a multiverse. First, it is useful to understand how our universe is believed to have come to be.

Around 13.7 billion years ago, simply speaking, everything we know of in the cosmos was an infinitesimal singularity. Then, according to theBig Bang theory, some unknown trigger caused it to expand and inflate in three-dimensional space. As the immense energy of this initial expansion cooled, light began to shine through. Eventually, the small particles began to form into the larger pieces of matter we know today, such as galaxies, stars and planets.

One big question with this theory is: are we the only universe out there. With our current technology, we are limited to observations within this universe because the universe is curved and we are inside the fishbowl, unable to see the outside of it (if there is an outside.)

There are at least five theories why a multiverse is possible, as a 2012 article explained

1. We don’t know what the shape of space-time is exactly. One prominent theory is that it is flat and goes on forever. This would present the possibility of many universes being out there. But with that topic in mind, it’s possible that universes can start repeating themselves. That’s because particles can only be put together in so many ways. More about that in a moment.

2. Another theory for multiple universes comes from “eternal inflation.” Based on research from Tufts University cosmologist Alexander Vilenkin, when looking at space-time as a whole, some areas of space stop inflating like the Big Bang inflated our own universe. Others, however, will keep getting larger. So if we picture our own universe as a bubble, it is sitting in a network of bubble universes of space. What’s interesting about this theory is the other universes could have very different laws of physics than our own, since they are not linked.

3. Or perhaps multiple universes can follow the theory of quantum mechanics (how subatomic particles behave), as part of the “daughter universe” theory. If you follow the laws of probability, it suggests that for every outcome that could come from one of your decisions, there would be a range of universes — each of which saw one outcome come to be. So in one universe, you took that job to China. In another, perhaps you were on your way and your plane landed somewhere different, and you decided to stay. And so on.

4. Another possible avenue is exploring mathematical universes, which, simply put, explain that the structure of mathematics may change depending in which universe you reside. “A mathematical structure is something that you can describe in a way that’s completely independent of human baggage,” said theory-proposer Max Tegmark of the Massachusetts Institute of Technology, as quoted in the 2012 article. “I really believe that there is this universe out there that can exist independently of me that would continue to exist even if there were no humans.”

5. And last but not least as the idea of parallel universes. To go back to the idea that space-time is flat, the number of possible particle configurations in multiple universes would be limited to 10^10^122 distinct possibilities, to be exact. So, with an infinite number of cosmic patches, the particle arrangements within them must repeat — infinitely many times over. This means there are infinitely many “parallel universes”: cosmic patches exactly the same as ours (containing someone exactly like you), as well as patches that differ by just one particle’s position, patches that differ by two particles’ positions, and so on down to patches that are totally different from ours.

– See more at:

Source: Parallel Universes: Theories & Evidence

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