hduarte1

[hduarte1]

🔷🔷🔷🔹🔹🔹🔹🔷🔷🔷 French mathematician and physicist Blaise Pascal (1623-62). I know not who sent me into the world, nor what the world is, nor what I myself am. I am terribly ignorant of everything. I know not what my body is, nor my senses, nor my soul and that part of me which thinks what I say, which reflects upon itself as well as upon all external things, and has no more knowledge of itself than of them. I see the terrifying immensity of the universe which surrounds me, and find myself limited to one corner of this vast expanse, without knowing why I am set down here rather than elsewhere, nor why the brief period appointed for my life is assigned to me at this moment rather than another in all the eternity that has gone before and will come after me. On all sides I behold nothing but infinity, in which I am a mere atom, a mere passing shadow that returns no more. All I know is that I must soon die, but what I understand least of all is this very death which I cannot escape. As I know not whence I come, so I know not whither I go. I only know that on leaving this world I fall for ever into nothingness or into the hands of a wrathful God, without knowing to which of these two states I shall be everlastingly consigned. Such is my condition, full of weakness and uncertainty. From all this I conclude that I ought to spend every day of my life without seeking to know my fate. I might perhaps be able to find a solution to my doubts; but I cannot be bothered to do so, I will not take one step towards its discovery.

[hduarte1]

[hduarte1]

[hduarte1]

[hduarte1]

[hduarte1]

SBPCh - Whale from Pavel Samokhvalov on Vimeo.

Video by Russian electronic band SBPCh - Whale Interesting visuals to say the least.  

#vimeo

[hduarte1]

The Moon’s shadow will dramatically affect insolation — the amount of sunlight reaching the ground — during the total solar eclipse. Credits: NASA's Scientific Visualization Studio

[hduarte1]

[hduarte1]

Equinox Earth Image Credit: Roscosmos / NTSOMZ / zelenyikot.livejournal.com Courtesy: Igor Tirsky, Vitaliy Egorov

Explanation: From a geostationary orbit 36,000 kilometers above the equator, Russian meteorological satellite Elektro-L takes high-resolution images of our fair planet every 30 minutes. But only twice a year, during an Equinox, can it capture an image like this one, showing an entire hemisphere bathed in sunlight.

At an Equinox, the Earth's axis of rotation is not tilted toward or away from the Sun, so the solar illumination can extend to both the planet's poles.

Of course, this Elektro-L picture was recorded on September 22nd,13 at the northern hemisphere's autumnal equinox.

For a moment on that date, the Sun was behind the geostationary satellite and a telltale glint of reflected sunlight is seen crossing the equator, at the location on the planet with satellite and sun directly overhead.

[hduarte1]

lighthouse.gif (640×480) - http://ligo.org/science/Publication-VSR4PulsarNarrowband/Images/lighthouse.gif

#TheShare

[hduarte1]

[hduarte1]

ringcross_cassini.gif (800×602) - https://apod.nasa.gov/apod/image/0701/ringcross_cassini.gif

#TheShare

[hduarte1]

[hduarte1]

[hduarte1]

[hduarte1]

NASA Continues to Study Pulsars, 50 Years After Their Chance Discovery

A little bit of “scruff” in scientific data 50 years ago led to the discovery of pulsars – rapidly spinning dense stellar corpses that appear to pulse at Earth.

Astronomer Jocelyn Bell made the chance discovery using a vast radio telescope in Cambridge, England. Although it was built to measure the random brightness flickers of a different category of celestial objects called quasars, the 4.5-acre telescope produced unexpected markings on Bell’s paper data recorder every 1.33730 seconds. The pen traces representing radio brightness revealed an unusual phenomenon.

“The pulses were so regular, so much like a ticking clock, that Bell and her supervisor Anthony Hewish couldn’t believe it was a natural phenomenon,” said Zaven Arzoumanian of NASA's Goddard Space Flight Center in Greenbelt, Maryland. “Once they found a second, third and fourth they started to think differently.”

The unusual stellar objects had been previously predicted but never observed. Today, scientists know of over 2,000 pulsars. These rotating “lighthouse” neutron stars begin their lives as stars between about seven and 20 times the mass of our sun. Some are found to spin hundreds of times per second, faster than the blades of a household blender, and they possess enormously strong magnetic fields.

animation showing aspects of a pulsar Most known neutron stars are observed as pulsars, emitting narrow, sweeping beams of radiation. They squeeze up to two solar masses into a city-size volume, crushing matter to the highest possible stable densities. To explore these exotic states of matter, NICER measures X-ray emissions across the surfaces of neutron stars as they spin, ultimately confronting the predictions of nuclear physics theory. Credits: NASA’s Goddard Space Flight Center

Technology advances in the past half-century allowed scientists to study these compact stellar objects from space using different wavelengths of light, especially those much more energetic than the radio waves received by the Cambridge telescope. Several current NASA missions continue to study these natural beacons.

The Neutron star Interior Composition Explorer, or NICER, is the first NASA mission dedicated to studying pulsars. In a nod to the anniversary of Bell’s discovery, NICER observed the famous first pulsar, known today as PSR B1919+21.

NICER launched to the International Space Station in early June and started science operations last month. Its X-ray observations – the part of the electromagnetic spectrum in which these stars radiate both from their million-degree solid surfaces and from their strong magnetic fields – will reveal how nature’s fundamental forces behave within the cores of these objects, an environment that doesn’t exist and can’t be reproduced anywhere else. "What's inside a pulsar?" is one of many long-standing astrophysics questions about these ultra-dense, fast-spinning, powerfully magnetic objects.

The “stuff” of pulsars is a collection of particles familiar to scientists from over a century of laboratory studies on Earth – neutrons, protons, electrons, and perhaps even their own constituents, called quarks. However, under such extreme conditions of pressure and density, their behavior and interactions aren’t well understood. New, precise measurements, especially of the sizes and masses of pulsars are needed to pin down theories.

“Many nuclear-physics models have been developed to explain how the make-up of neutron stars, based on available data and the constraints they provide,” said Goddard’s Keith Gendreau, the principal investigator for NICER. “NICER’s sensitivity, X-ray energy resolution and time resolution will improve these by more precisely measuring their radii, to an order of magnitude improvement over the state of the art today.”

[hduarte1]

(via gemiShareTweetEmailMoreSavenids.gif (GIF Image, 600 × 338 pixel

An excerpt of an animated simulation of the Geminids meteor shower, which peaks in December. The blue circle and dot is Earth's orbit of the sun. Save