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😗😁Year 2015


(12 Apr 1997) English/Nat.
British and Dutch scientists using a giant magnetic field have made a frog float in mid-air, and might even be able to do the same thing with a human being.
The team from Britain’s University of Nottingham and the University of Nijmegen in the Netherlands has also succeeded in levitating plants, grasshoppers and fish.
Scientists at the University of Nijmegen in Holland have managed to make a frog float six feet (approximately two metres) in the air — and they say the trick could easily be repeated with a human.
The secret is not magic but a powerful magnetic field which overcomes the force of gravity.
The field makes the frog’s atoms generate a weak magnetic force in the opposite direction.
This causes it to be repelled in the same way as like poles of two magnets.
Plants, grasshoppers and fish have been levitated by the research team in the same way.
NASA, apparently, is extremely interested in the experiment in order to be able to test the effects of weightlessness on astronauts without having to put them into space.
Easy, says team leader Dr Andre Geim.
SOUNDBITE: (English)
There is no problem with putting a man by this magnetic levitation, to fly in the air. Technically we can do it with you without any problems.
SUPER CAPTION: Dr Andre Geim, Director of the High Field Magnetic Laboratory of the Catholic University of Nijmegen.
And for those worried about the effects on the frog — don’t worry.
He’s not hopping mad — quite the opposite, in fact.

Find out more about AP Archive: http://www.aparchive.com/HowWeWork.

Last year, the Hubble Space Telescope made headlines by detecting the most distant star ever seen, a luminary from the universe’s first billion years named “Earendel.” Now, NASA’s James Webb Space Telescope has uncovered mesmerizing details about this intriguing star.

“The Hubble provided us a glimpse of Earendel, but the James Webb Space Telescope is now offering us a deep dive,” said NASA. “These observations not only enlighten us about the star’s nature but also about its host galaxy, the Sunrise Arc, and possibly about the early universe itself.”

Earendel is no ordinary star. Webb’s NIRCam (Near-Infrared Camera) instrument paints a portrait of a massive B-type star, sizzling at temperatures twice as scorching as our Sun and radiating with a luminosity a million times more intense.

I am studying Noether’s theorem in field theory and I am not understanding what spacelike-surfaces mean. I will reproduce the bit of the argument below that contains the term “spacelike-sufaces” in the context I am not understanding.

There will be a conserved ccurrent for each group generator $a$. Each will result in a conserved charge (that is, an integral of motion). To see this, take in spacetime a volume unbounded in the space-like direction, but limited in time by two space-like surfaces $w_1$ and $w_2$. Integrating $\partial_{\mu} J^{\mu}_a=0$ over this volume, we get an integral over the boundary surface, composed of $w_1$, $w_2$ and the time-like boundaries supposed to be at infinity. If we now suppose the current to be zero at infinity on these boundaries, we remain with.

$$\int_{w_1}d\sigma_{\mu} J^{\mu}_a=\int_{w_2}d\sigma_{\mu} J^{

The hints pointing to two galaxies are found in the question mark’s strange shape. There are two brighter spots, one in the curve and the other in the dot, which could be the galactic nuclei, or the centers of the galaxies, Britt says. The curve of the question mark might be the “tails” being stripped off as the two galaxies spiral toward each other.

“It’s very cute. It’s a question mark 
 But you can find the colons and semicolons, and any other punctuation mark, because you have 10,000 little smudges of light in each image taken every half hour,” says David Helfand, an astronomer at Columbia University. The sheer number of shining objects we find are bound to create some serendipitous images, and our brains have evolved to find those patterns, he says.

Astronomers have seen similar objects closer to home. Two merging galaxies captured by the Hubble Space Telescope in 2008 also look like a question mark, just turned 90 degrees.

The universe is humming with gravitational radiation—a very low-frequency rumble that rhythmically stretches and compresses spacetime and the matter embedded in it.

That is the conclusion of several groups of researchers from around the world who simultaneously published a slew of journal articles in June describing more than 15 years of observations of millisecond pulsars within our corner of the Milky Way galaxy. At least one group—the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) collaboration—has found compelling evidence that the precise rhythms of these pulsars are affected by the stretching and squeezing of spacetime by these long-wavelength .

“This is key evidence for gravitational waves at very low frequencies,” says Vanderbilt University’s Stephen Taylor, who co-led the search and is the current chair of the collaboration. “After years of work, NANOGrav is opening an entirely new window on the gravitational-wave universe.”

NASA has reestablished connection with Voyager 2 after a tense two weeks of not hearing anything from the probe. On July 21st, the agency lost contact with Voyager 2 following a series of planned commands that mistakenly pointed it two degrees away from our planet. While it is scheduled to automatically reset its orientation on October 15th, it’s not surprising that NASA scientists didn’t just wait for that date to know whether the spacecraft is still running. Voyager 2 was launched way back in 1977, and it’s one of the only two probes sending us back valuable data on interstellar space.

For a few days after July 21st, NASA wasn’t even sure what the spacecraft’s condition was. It wasn’t until August 1st that multiple ground antennas from the Deep Space Network (DSN) were able to detect a carrier signal from the probe. A carrier signal is what a spacecraft uses to beam data back to the ground, but NASA said the one DSN detected was too weak to be able to transmit any information. Still, it was enough to confirm that Voyager 2 was still working and that it hadn’t deviated from its trajectory.

Instead of simply waiting for October, Voyager’s ground team decided to take action. They concocted a plan to “shout” a command to the spacecraft across over 12.3 billion miles of space using the DSN, telling it to turn its antenna back to Earth. The whole process illustrated just how vast outer space truly is: It took 18.5 hours for that message to reach the probe, and another 18.5 hours for NASA to start receiving science and telemetry data again, indicating that Voyager 2 had received the command.

The Universe we live in is a transparent one, where light from stars and galaxies shines bright against a clear, dark backdrop.

But this wasn’t always the case – in its early years, the Universe was filled with a fog of hydrogen atoms that obscured light from the earliest stars and galaxies.

The intense ultraviolet light from the first generations of stars and galaxies is thought to have burned through the hydrogen fog, transforming the Universe into what we see today.

Using a private observatory, astronomers have performed the first photometric study of a peculiar W UMa-type binary known as CSS J003106.8+313347. Results of the study, published July 27 on the preprint server arXiv, shed more light on the properties of this system.

In general, W Ursae Majoris-type, or W UMa-type binaries (EWs) are eclipsing binaries with a short orbital period (below one day) and continuous light variation during a cycle. They are composed of two with similar temperature and luminosity, sharing a common envelope of material and are thus in contact with one another. Therefore, they are often dubbed “contact binaries.”

Located some 4,900 away, CSS J003106.8+313347 is an EW with an apparent magnitude of 14.73. The orbital period of the system is estimated to be approximately 0.344 days.