Science Pics of the Week: The origin of gravitational waves

Friday, February 12, 2016, 11:08 AM - Where did the gravitational waves come from? Plus making sense of Pluto’s surprising geological complexity, and a striking panorama of a enigmatic Martian sand dune. It's Science Pics of the Week!

Where did they come from?

On Thursday, February 11, scientists with LIGO - Laser Interferometer Gravitational-Wave Observatory - announced something amazing. 100 years after Einstein predicted their existence, we have finally detected gravitational waves.

The researches gave an excellent explanation of exactly how these waves were formed and how they were detected, but where, exactly, did they come from?

According to LIGO:

The approximate location of the source of gravitational waves detected on September 14, 2015, by the twin LIGO facilities is shown on this sky map of the southern hemisphere. The colored lines represent different probabilities for where the signal originated: the purple line defines the region where the signal is predicted to have come from with a 90 percent confidence level; the inner yellow line defines the target region at a 10 percent confidence level.
The gravitational waves were produced by a pair of merging black holes located 1.3 billion light-years away.
A small galaxy near our own, called the Large Magellanic Cloud, can be seen as a fuzzy blob underneath the marked area, while an even smaller galaxy, called the Small Magellanic Cloud, is below it.
Researchers were able to home in on the location of the gravitational-wave source using data from the LIGO observatories in Livingston, Louisiana, and Hanford, Washington. The gravitational waves arrived at Livingston 7 milliseconds before arriving at Hanford. This time delay revealed a particular slice of sky, or ring, from which the signal must have arisen. Further analysis of the varying signal strength at both detectors ruled out portions of the ring, leaving the remaining patch shown on this map.
In the future, when additional gravitational-wave detectors are up and running, scientists will be able to pinpoint more precisely the locations and sources of signals.

Mapping Pluto's complex geology

With all the imagery and data from Pluto downlinked from the New Horizons spacecraft, scientists have been hard at work, poring over all that information to finally give us a comprehensive look at a planet that has largely been a mystery to us since its discovery, nearly 86 years ago.

The latest addition is here:

Pluto geological map with reference to the now well-known visible maps of Pluto's surface. Credits: NASA/JHUAPL/SwRI

According to NASA:

This map covers a portion of Pluto’s surface that measures 1,290 miles (2,070 kilometers) from top to bottom, and includes the vast nitrogen-ice plain informally named Sputnik Planum and surrounding terrain. As the key in the figure below indicates, the map is overlaid with colors that represent different geological terrains. Each terrain, or unit, is defined by its texture and morphology – smooth, pitted, craggy, hummocky or ridged, for example. How well a unit can be defined depends on the resolution of the images that cover it. All of the terrain in this map has been imaged at a resolution of approximately 1,050 feet (320 meters) per pixel or better, meaning scientists can map units with relative confidence.
The various blue and greenish units that fill the center of the map represent different textures seen across Sputnik Planum, from the cellular terrain in the center and north, to the smooth and pitted plains in the south. The black lines represent troughs that mark the boundaries of cellular regions in the nitrogen ice. The purple unit represents the chaotic, blocky mountain ranges that line Sputnik’s western border, and the pink unit represents the scattered, floating hills at its eastern edge. The possible cryovolcanic feature informally named Wright Mons is mapped in red in the southern corner of the map. The rugged highlands of the informally named Cthulhu Regio are mapped in dark brown along the western edge, pockmarked by many large impact craters, shown in yellow.

The details of Pluto's complex geology, with handy guide to its terrain and features. Credits: NASA/JHUAPL/SwRI

Examining Pluto's various terrain features in detail gives the scientists an idea of exactly what processes are in play on the dwarf planet's surface, and the timeline of how those features evolved.

Take a spin near a Martian sand dune!

Mars rover Curiosity has been doing the very first close-up work on a Martian sand dune lately, and it took an amazing 360 degree panorama of its environment to share with those of us stuck back here on Earth.

Although the above embedded frame is from the YouTube channel of NASA's Jet Propulsion Laboratory, and it certainly has the appearance of a 2-minute-long video, it's actually not.

Press the "Play" button on it, give it a few seconds until the logo vanishes and pause it. Use the settings "cog" to increase the resolution up as high as your computer or device can handle (it goes all the way up to 4K!) and then interact with the view as you would any 360 degree panorama. Click or tap and drag left, right, up or down (or use the convenient controls at the top left of the view), and you can get a sense of what it would be like to stand on the surface of Mars.

If you can go full screen and 4K resolution, I highly recommend it!

Sources: Caltech/LIGO | NASA | NASA JPL

Watch below: The Journey of a Gravitational Wave