Robert H. Goddard, considered the father of modern rocketry, was born in Worcester Massachusetts in 1882. As a 16 year old, Goddard read H.G. Wells' science fiction classic "War Of The Worlds" and dreamed of space flight. By 1926 he had designed, built, and flown the world's first liquid fuel rocket. Launched 100 years ago, on March 16, 1926 from his aunt Effie's farm in Auburn Massachusetts, the rocket dubbed "Nell", rose to an altitude of 41 feet in a flight that lasted about 2 1/2 seconds. In this posed photo Goddard stands next to the 10 foot tall rocket, holding the launch stand frame. To achieve a stable flight without the need for fins, the rocket's heavy motor was located at the top, fed by lines from liquid oxygen and gasoline fuel tanks at the bottom. Widely recognized as a gifted experimenter and engineering genius, his rockets were many years ahead of their time. Goddard was awarded over 200 patents in rocket technology, most of them after his death in 1945. A liquid fuel rocket constructed on principles developed by Goddard landed humans on the Moon in 1969. via NASA https://ift.tt/Umd8Iyf

Scanning the skies for galaxies, Canadian astronomer Paul Hickson and colleagues identified some 100 compact groups of galaxies, now appropriately called Hickson Compact Groups. The four prominent galaxies seen in this intriguing telescopic skyscape are one such group, Hickson 44. The Hickson 44 galaxy group is about 100 million light-years distant, far beyond the foreground Milky Way stars, toward the northern springtime constellation Leo. The two spiral galaxies in the center of the image are edge-on NGC 3190 with distinctive, warped dust lanes, and S-shaped NGC 3187. Along with the bright elliptical, NGC 3193 (left) they are also known as Arp 316. The spiral toward the lower right corner is NGC 3185, the 4th member of the Hickson group. Like other galaxies in Hickson groups, these show signs of distortion and enhanced star formation, evidence of a gravitational tug of war that will eventually result in galaxy mergers on a cosmic timescale. The merger process is now understood to be a normal part of the evolution of galaxies, including our own Milky Way. For scale, NGC 3190 is about 75,000 light-years across at the estimated distance of Hickson 44. via NASA https://ift.tt/zEaCjgh

What is the sound of two black holes merging in deep space? Sound waves don't propagate in vacuum, but gravitational waves do. In 2015 we were able to "hear" them for the first time and confirm one of Albert Einstein's theoretical predictions. Each square on the grid of the featured image represents one of the gravitational wave detections announced so far by the LIGO-VIRGO-KAGRACollaboration. These plots show how the binary pair accelerates in their orbit around each other towards merger: the rising frequency effect is called a "chirp". Although there are significantly more neutron stars than black holes, most of the detections are binary black hole mergers. That happens because black holes are heavier and their signals are louder and can be seen farther away, resulting in more detections. These events are rare, and we don't expect to see one close by in our Galaxy any time soon. But they are happening continuously throughout the cosmos. via NASA https://ift.tt/B8AzEsH

In the words of today's astrophotographer, Rositsa Dimitrova, "What have these silent sentinels watched pass across the sky?" The volcanic mo'ai (meaning statue) of Ahu Tongariki stand guard over Rapa Nui (Isla de Pascua, Easter Island), a Polynesian island (annexed by Chile in 1888) located thousands of kilometers off the coast of South America in the Pacific Ocean. Due to the island's remoteness, the mo'ai, with their backs to the dark ocean, are able to gaze upon a clear and vibrant night sky. Pictured, these larger-than-life statues stare at the bright band of the Milky Way, partly obscured by interstellar dust and blurred by Earth's clouds. Under such clear night skies, the Rapa Nui created observatories and used astronomical observations for navigation, calendar calibration, celebrations, and more. Images like this one remind us of the importance of dark skies, protecting the land underneath them, and preserving the culture that they inspire. via NASA https://ift.tt/15jrVa8

What's happening at the end of that street? Pictured here are not auroras but light pillars, a phenomenon typically much closer. In most places on Earth, a lucky viewer can see a Sun pillar, a column of light appearing to extend up from the Sun caused by flat fluttering ice-crystals reflecting sunlight from the upper atmosphere. Usually, these ice crystals evaporate before reaching the ground. During freezing temperatures, however, flat fluttering ice crystals may form near the ground and are sometimes known as a crystal fog. These small ice crystals may then reflect not the Sun but ground lights. The featured image captured not only numerous light pillars but also the iconic constellation of Orion, and was taken in Mohe, the northernmost city in China. via NASA https://ift.tt/hQF9VEY

Spiral NGC 1300 and elliptical NGC 1297 are galaxies that lie on the banks of the southern constellation Eridanus (The River). At 70 million light-years distant or more, both are members of the Eridanus Galaxy Cluster. About 100,000 light-years across, at lower left in this sharp, galaxy group photo NGC 1300 is seen face-on with a prominent central bar and grand, sweeping spiral arms. Like other spiral galaxies, including our own barred spiral Milky Way Galaxy, NGC 1300 is thought to have a supermassive central black hole. A contrast in appearance and slightly more distant, NGC 1297 is the roughly spherical large elliptical galaxy near the top of the frame. With little active star formation, elliptical galaxies are composed of older populations of stars and are likely he result of multiple collisions and mergers with spirals. via NASA https://ift.tt/q4VWHOg

The defining astronomical moment of the equinox today is at 14:46 UTC (March 20). That's when the Sun crosses the celestial equator moving north in its yearly journey through planet Earth's sky, marking the beginning of spring for our fair planet in the northern hemisphere and fall in the southern hemisphere. Then, day and night are nearly equal around the globe. In fact, both day and nighttime exposures from a spring equinox at the Observatorio del Teide in Tenerife, Canary Islands, Spain, are used in this composited skyscape. Over 1,000 images were taken with a fisheye lens and merged in the ambitious equinox project. The apparent motion of the Sun setting along the celestial equator on the equinox date follows the bright linear, diagonal track from the sequence of daytime exposures taken over 6 hours. After sunset, nighttime exposures recorded startrails, with the celestial equator as a linear track and concentric arcs circling the north celestial pole near Polaris at upper right and the south celestial pole beyond the lower left edge (and below the Teide horizon). The foreground includes the distant Teide volcano peak and the observatory's pyramid-shaped solar laboratory building. via NASA https://ift.tt/r6atN0Q