Hilarious Animal Snapchats That Are Impossible Not To Laugh At

Take me back to California 🌴❤️

Lunar eclipse 2019 

Image credit: Dan Wery

Mis conversaciones favoritas son aquellas que se tienen con el lápiz y el papel. 

-Zufriedenheit. 

Pulsar planets are planets that are found orbiting pulsars, or rapidly rotating neutron stars. The first such planet to be discovered was around a millisecond pulsar and was the first extrasolar planet to be confirmed as discovered.

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What is Gravitational Lensing?

A gravitational lens is a distribution of matter (such as a cluster of galaxies) between a distant light source and an observer, that is capable of bending the light from the source as the light travels towards the observer. This effect is known as gravitational lensing, and the amount of bending is one of the predictions of Albert Einstein’s general theory of relativity.

This illustration shows how gravitational lensing works. The gravity of a large galaxy cluster is so strong, it bends, brightens and distorts the light of distant galaxies behind it. The scale has been greatly exaggerated; in reality, the distant galaxy is much further away and much smaller. Credit: NASA, ESA, L. Calcada

There are three classes of gravitational lensing:

1° Strong lensing: where there are easily visible distortions such as the formation of Einstein rings, arcs, and multiple images.

Einstein ring. credit: NASA/ESA&Hubble

2° Weak lensing: where the distortions of background sources are much smaller and can only be detected by analyzing large numbers of sources in a statistical way to find coherent distortions of only a few percent. The lensing shows up statistically as a preferred stretching of the background objects perpendicular to the direction to the centre of the lens. By measuring the shapes and orientations of large numbers of distant galaxies, their orientations can be averaged to measure the shear of the lensing field in any region. This, in turn, can be used to reconstruct the mass distribution in the area: in particular, the background distribution of dark matter can be reconstructed. Since galaxies are intrinsically elliptical and the weak gravitational lensing signal is small, a very large number of galaxies must be used in these surveys.

The effects of foreground galaxy cluster mass on background galaxy shapes. The upper left panel shows (projected onto the plane of the sky) the shapes of cluster members (in yellow) and background galaxies (in white), ignoring the effects of weak lensing. The lower right panel shows this same scenario, but includes the effects of lensing. The middle panel shows a 3-d representation of the positions of cluster and source galaxies, relative to the observer. Note that the background galaxies appear stretched tangentially around the cluster.

3° Microlensing: where no distortion in shape can be seen but the amount of light received from a background object changes in time. The lensing object may be stars in the Milky Way in one typical case, with the background source being stars in a remote galaxy, or, in another case, an even more distant quasar. The effect is small, such that (in the case of strong lensing) even a galaxy with a mass more than 100 billion times that of the Sun will produce multiple images separated by only a few arcseconds. Galaxy clusters can produce separations of several arcminutes. In both cases the galaxies and sources are quite distant, many hundreds of megaparsecs away from our Galaxy.

Gravitational lenses act equally on all kinds of electromagnetic radiation, not just visible light. Weak lensing effects are being studied for the cosmic microwave background as well as galaxy surveys. Strong lenses have been observed in radio and x-ray regimes as well. If a strong lens produces multiple images, there will be a relative time delay between two paths: that is, in one image the lensed object will be observed before the other image.

As an exoplanet passes in front of a more distant star, its gravity causes the trajectory of the starlight to bend, and in some cases results in a brief brightening of the background star as seen by a telescope. The artistic concept illustrates this effect. This phenomenon of gravitational microlensing enables scientists to search for exoplanets that are too distant and dark to detect any other way.Credits: NASA Ames/JPL-Caltech/T. Pyle

Explanation in terms of space–time curvature

Simulated gravitational lensing by black hole by: Earther

In general relativity, light follows the curvature of spacetime, hence when light passes around a massive object, it is bent. This means that the light from an object on the other side will be bent towards an observer’s eye, just like an ordinary lens. In General Relativity the speed of light depends on the gravitational potential (aka the metric) and this bending can be viewed as a consequence of the light traveling along a gradient in light speed. Light rays are the boundary between the future, the spacelike, and the past regions. The gravitational attraction can be viewed as the motion of undisturbed objects in a background curved geometry or alternatively as the response of objects to a force in a flat geometry.

A galaxy perfectly aligned with a supernova (supernova PS1-10afx) acts as a cosmic magnifying glass, making it appear 100 billion times more dazzling than our Sun. Image credit: Anupreeta More/Kavli IPMU.

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Hurricanes Have No Place to Hide, Thanks to Better Satellite Forecasts

If you’ve ever looked at a hurricane forecast, you’re probably familiar with “cones of uncertainty,” the funnel-shaped maps showing a hurricane’s predicted path. Thirty years ago, a hurricane forecast five days before it made landfall might have a cone of uncertainty covering most of the East Coast. The result? A great deal of uncertainty about who should evacuate, where it was safe to go, and where to station emergency responders and their equipment.

Over the years, hurricane forecasters have succeeded in shrinking the cone of uncertainty for hurricane tracks, with the help of data from satellites. Polar-orbiting satellites, which fly nearly directly above the North and South Poles, are especially important in helping cut down on forecast error.

The orbiting electronic eyeballs key to these improvements: the Joint Polar Satellite System (JPSS) fleet. A collaborative effort between NOAA and NASA, the satellites circle Earth, taking crucial measurements that inform the global, regional and specialized forecast models that have been so critical to hurricane track forecasts.

The forecast successes keep rolling in. From Hurricanes Harvey, Irma and Maria in 2017 through Hurricanes Florence and Michael in 2018, improved forecasts helped manage coastlines, which translated into countless lives and property saved. In September 2018, with the help of this data, forecasters knew a week ahead of time where and when Hurricane Florence would hit. Early warnings were precise enough that emergency planners could order evacuations in time — with minimal road clogging.  The evacuations that did not have to take place, where residents remained safe from the hurricane’s fury, were equally valuable.

The satellite benefits come even after the storms make landfall. Using satellite data, scientists and forecasters monitor flooding and even power outages. Satellite imagery helped track power outages in Puerto Rico after Hurricane Maria and in the Key West area after Hurricane Irma, which gave relief workers information about where the power grid was restored – and which regions still lacked electricity. 

Flood maps showed the huge extent of flooding from Hurricane Harvey and were used for weeks after the storm to monitor changes and speed up recovery decisions and the deployment of aid and relief teams.

As the 2019 Atlantic hurricane season kicks off, the JPSS satellites, NOAA-20 and Suomi-NPP, are ready to track hurricanes and tropical cyclones as they form, intensify and travel across the ocean – our eyes in the sky for severe storms. 

For more about JPSS, follow @JPSSProgram on Twitter and facebook.com/JPSS.Program, or @NOAASatellites on Twitter and facebook.com/NOAASatellites.

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Happy Birthday To Vera Rubin: The Mother Of Our Dark Matter Universe

“Dark matter should drive the formation of structure on all large scales, with every galaxy consisting of a large, diffuse halo of dark matter that is far less dense and more diffuse than the normal matter. While the normal matter clumps and clusters together, since it can stick together and interact, dark matter simply passes through both itself and normal matter. Without dark matter, the Universe wouldn’t match our observations.

But this branch of science truly got its start with the revolutionary work of Vera Rubin. While many, including me, will deride the Nobel committee for snubbing her revolutionary science, she truly did change the Universe. On what would have been her 91st birthday, remember her in her own words:

“Don’t let anyone keep you down for silly reasons such as who you are, and don’t worry about prizes and fame. The real prize is finding something new out there.”

50 years later, we’re still investigating the mystery Vera Rubin uncovered. May there always be more to learn.”

Today, dark matter is practically accepted as a given, owing to an overwhelming suite of evidence that points to its existence. Without adding dark matter as an ingredient, we simply can’t explain the Universe, from gravitational lensing to large-scale structure to Big Bang nucleosynthesis to the cosmic microwave background and much more. But throughout the 1930s, 40s and 50s, no one would even give the idea a second thought. Until, that is, Vera Rubin came along and changed everything. 

Today would have been her 91st birthday, and it’s about time you got the scientific story to celebrate what she taught us all.

11/08/18

Jovian Close Encounter

A multitude of magnificent, swirling clouds in Jupiter’s dynamic North North Temperate Belt is captured in this image from NASA’s Juno spacecraft. Appearing in the scene are several bright-white “pop-up” clouds as well as an anticyclonic storm, known as a white oval. This color-enhanced image was taken at 1:58 p.m. PDT on Oct. 29, 2018 (4:58 p.m. EDT) as the spacecraft performed its 16th close flyby of Jupiter. At the time, Juno was about 4,400 miles (7,000 kilometers) from the planet’s cloud tops, at a latitude of approximately 40 degrees north. Citizen scientists Gerald Eichstädt and Seán Doran created this image using data from the spacecraft’s JunoCam imager. JunoCam’s raw images are available for the public to peruse and to process into image products at: http://missionjuno.swri.edu/junocam.

During its continued mission, NASA’s Juno spacecraft will maintain its 53-day polar orbit around Jupiter. At its closest, Juno passes within 3,000 miles (5,000 kilometers) of Jupiter’s cloud tops once during each 53-day orbit. At the high end of each orbit, Juno is about 5 million miles (8-million kilometers) from the planet – which is just beyond the orbit of the Jovian moon Themisto. Credits: NASA/JPL-Caltec

The year is 1965, and thanks to telecommunication engineers at our Jet Propulsions Laboratory, the first color version of one of our first Martian images had been created. Brought to life by hand coloring numbered strips, this image is a true blast to the past.

Fast forward to the 21st century and our Mars InSight mission now enables us to gawk at the Martian horizon as if we were there. InSight captured this panorama of its landing site on Dec. 9, 2018, the 14th Martian day, or sol, of its mission. The 290-degree perspective surveys the rim of the degraded crater InSight landed in and was made up of 30 photos stitched together.

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