nihalehalvmaane:

What I learned from studying math at school.

holymoleculesbatman:

Molecules with Strange Names: SEX (Sodium Ethyl Xanthate)

It is an organosulfur compound with the chemical formula CH₃CH₂OCS₂. It is a pale yellow powder, which characteristically hydrolyzes to release malodorous products. Sodium ethyl xanthate is predominantly used in the mining industry as a flotation agent. 

ikenbot:

New Research Confirms The Existence of Dark Matter

Image: Don Dixon

Fans of dark matter can rest easy. A study published last month raised eyebrows by suggesting that our cosmic neighbourhood is empty of the extra mass needed to hold the galaxy together. But a re-analysis shows that the dark matter was there all along.

Dark matter is the mysterious, invisible stuff that makes up 83 per cent of the matter in the universe. It is responsible for keeping galaxies from flying apart despite their high spinning speeds, and has aided our understanding of how structures in the universe formed.

The most popular theories say that dark matter is a hitherto undetected particle called a WIMP (weakly interacting massive particle) that is shy of interacting with ordinary matter through any force except gravity.

But several underground detectors waiting for WIMPs have come up empty, or with conflicting results. If the galaxy is so full of dark matter, why hasn’t it shown up yet?

In April, a team led by Christian Moni-Bidin of the University of Concepcion in Chile thought they had a solution: the WIMPs aren’t actually there.

The team tracked the motions of more than 400 stars within 13,000 light years of Earth to estimate the mass of matter – visible and dark – in the sun’s local neighbourhood. They concluded that the mass they found could be explained by the visible matter alone, with no need for dark matter.

But the team made a subtle error, say Jo Bovy and Scott Tremaine of the Institute for Advanced Study in Princeton, New Jersey.

Moni-Bidin and colleagues considered stars whose orbits take them far above or below the Milky Way’s main bright disc, and used the speed at which they orbit the centre of the galaxy to figure out how much of a pull they feel from the nearby mass of stars and dark matter. They assumed that the stars’ speeds would be the same no matter how far they were from the galactic centre. Observations of dust clumps have shown that this assumption is true for young stars orbiting in the galactic disc, which mostly move in a near-perfect circle.

But the stars that orbit high above or far below the disc can’t have circular orbits, Bovy says. The only stars that reach such great heights have been kicked away from the disc by matter in the galaxy’s spiral arms, which sent them on highly elliptical orbits.

Full Article: Crisis averted: Dark matter was there all along

quantumaniac:

Galilean Telescope

In 1609, Galileo Galilei revolutionized science forever with his design of a telescope - now commonly referred to as a Galilean telescope. it uses a convergent objective lens in combination with a divergent eyepiece lens in order to produce an upright image. 

At best, Galileo’s telescope magnified objects about 30 times - but the images were blurry and distorted. Despite the challenges, Galileo was still able to explore the phases of Venus, as well as the four moons of Jupiter and craters on our own moon. 

Parallel rays of light from a distant object (y) would be brought to a focus in the focal plane of the objective lens (F’ L1 / y’). The (diverging) eyepiece (L2) lens intercepts these rays and renders them parallel once more. Non-parallel rays of light from the object traveling at an angle α1 to the optical axis travel at a larger angle (α2 > α1) after they passed through the eyepiece. This leads to an increase in the apparent angular size and is responsible for the perceived magnification.

The final image (y’’) is a virtual image, located at infinity and is the same way up as the object.

ikenbot:

Near-Death Experiences are Lucid Dreams, Experiment Finds

In a new exercise by a California organization that studies lucid dreaming, volunteers have been conditioned to dream near-death experiences, including the classic scenario of flying toward a light at the end of a tunnel. The researchers say their experiment demonstrates that these heavenly visions must be products of the human mind rather than supernatural phenomena.

In the sleep experiment at the Out-Of-Body Experience Research Center in Los Angeles, four groups of 10 to 20 volunteers were trained to perform a series of mental steps upon awakening during the night that might lead them to have out-of-body experiences. If able to “separate” from their bodies, they were then conditioned to try dreaming about floating through a tunnel toward a bright light. Eighteen of the volunteers said they were able to dream such an experience.

“Some of the test subjects not only succeeded in reproducing the out-of-body flight through a tunnel, but also enjoyed the ecstasy typical of the experience, and even flew all the way to the light and met their deceased relatives there,” center leader Michael Raduga stated in a press release about the work, which has not been published in a peer-reviewed journal.

More than 8 million Americans have had a near-death experience, and they most often occur during states of anesthesia-induced sleep, according to the center. Prior work by neurologists, including Kevin Nelson of the University of Kentucky, suggests that NDEs are indeed generated by the same brain mechanisms that cause lucid dreams. Nelson’s research shows that both types of experiences arise when part of the brain called the dorsolateral prefrontal region — our “logical center,” which is usually active only when we’re awake — becomes active during REM sleep, allowing extremely vivid dreams that seem to be happening in real life. He calls the transitional state between dreaming and wakefulness a “borderland of consciousness” and believes it is in this mixed state that lucid dreams and NDEs occur.

With Nelson’s research in mind, Raduga designed his experiment to determine if volunteers could be coached to dream up NDEs when in the transitional phase between sleep and waking. This would demonstrate that reports of NDEs, which are commonly cited as proof of the supernatural, really are just lucid dreams.

Volunteers who successfully generated NDEs described their experiences for the researchers. One participant, identified by the center asNadezhda S., stated: “I was able to leave my body after a couple of tries. Now that I was out of my body, I wanted to see the tunnel and it immediately appeared in front of me … Once I flew to the end of that tunnel … I saw my deceased husband there in the spirit. We spoke for several minutes. His words, touch, bearing, and feelings were real, just like during his life. Later on, when I felt it was time to leave, I went up to the tunnel, jumped and gently landed in my body.”

Continue..

For more on Dreams, visit ikenbot.tumblr.com/dreams

spatiale:

untitled (by rhyme of another summer)

pencilpoetry:

My last physics project presenting stellar evolution.

I should be studying for finals…