What’s happening behind Uluru? A United Nations World Heritage Site, Uluru is an extraordinary 350-meter high mountain in central Australia that rises sharply from nearly flat surroundings. Composed of sandstone, Uluru has slowly formed over the past 300 million years as softer rock eroded away. In the background of the featured image taken in mid-May, a raging thunderstorm is visible. Far behind both Uluru and the thunderstorm is a star-filled sky highlighted by the constellation of Orion. The Uluru region has been a home to humans for over 22,000 years. Local indigenous people have long noted that when the stars that compose the modern constellation of Orion first appear in the night sky, a hot season involving lightning storms will soon be arriving. via NASA https://ift.tt/3uy2PLM

Clusters of stars can be near or far, young or old, diffuse or compact. The featured image shows two quite contrasting open star clusters in the same field. M35, on the lower left, is relatively nearby at 2800 light years distant, relatively young at 150 million years old, and relatively diffuse, with about 2500 stars spread out over a volume 30 light years across. Bright blue stars frequently distinguish younger open clusters like M35. Contrastingly, NGC 2158, on the upper right, is four times more distant than M35, over 10 times older, and much more compact. NGC 2158’s bright blue stars have self-destructed, leaving cluster light to be dominated by older and yellower stars. In general, open star clusters are found in the plane of our Milky Way Galaxy, and contain anywhere from 100 to 10,000 stars — all of which formed at nearly the same time. Both open clusters M35 and NGC 2158 can be found together with a small telescope toward the constellation of the Twins (Gemini). via NASA https://ift.tt/3eD2xxT

The dark Horsehead Nebula and the glowing Orion Nebula are contrasting cosmic vistas. Adrift 1,500 light-years away in one of the night sky’s most recognizable constellations, they appear in opposite corners of the above stunning mosaic. The familiar Horsehead nebula appears as a dark cloud, a small silhouette notched against the long red glow at the lower left. Alnitak is the easternmost star in Orion’s belt and is seen as the brightest star to the left of the Horsehead. Below Alnitak is the Flame Nebula, with clouds of bright emission and dramatic dark dust lanes. The magnificent emission region, the Orion Nebula (aka M42), lies at the upper right. Immediately to its left is a prominent reflection nebula sometimes called the Running Man. Pervasive tendrils of glowing hydrogen gas are easily traced throughout the region. via NASA https://ift.tt/3o7w6KT

In this evocative night scene a dusty central Milky Way rises over the ancient Andean archaeological site of Yacoraite in northwestern Argentina. The denizens of planet Earth reaching skyward are the large Argentine saguaro cactus currently native to the arid region. The unusual yellow-hued reflection nebula above is created by dust scattering starlight around red giant star Antares. Alpha star of the constellation Scorpius, Antares is over 500 light-years distant. Next to it bright blue Rho Ophiuchi is embedded in more typical dusty bluish reflection nebulae though. The deep night skyscape was created from a series of background exposures of the rising stars made while tracking the sky, and a foreground exposure of the landscape made with the camera and lens fixed on the tripod. In combination they produce the single stunning image and reveal a range of brightness and color that your eye can’t quite perceive on its own. via NASA https://ift.tt/3o0iCAM

Sixty years ago, near the dawn of the space age, NASA controllers « lit the candle » and sent Mercury astronaut Alan Shepard arcing into space atop a Redstone rocket. His cramped space capsule was dubbed Freedom 7. Broadcast live to a global television audience, the historic Mercury-Redstone 3 (MR-3) spacecraft was launched from Cape Canaveral Florida at 9:34 a.m. Eastern Time on May 5, 1961. The flight of Freedom 7, the first space flight by an American, followed less than a month after the first human venture into space by Soviet Cosmonaut Yuri Gagarin. The 15 minute sub-orbital flight achieved an altitude of 116 miles and a maximum speed of 5,134 miles per hour. As Shepard looked back near the peak of Freedom 7’s trajectory, he could see the outlines of the west coast of Florida, Lake Okeechobe in central Florida, the Gulf of Mexico, and the Bahamas. Shepard would later view planet Earth from a more distant perspective and walk on the Moon as commander of the Apollo 14 mission. via NASA https://ift.tt/2RsHkgO

NGC 3199 lies about 12,000 light-years away, a glowing cosmic cloud in the nautical southern constellation of Carina. The nebula is about 75 light-years across in this narrowband, false-color view. Though the deep image reveals a more or less complete bubble shape, it does look very lopsided with a much brighter edge along the top. Near the center is a Wolf-Rayet star, a massive, hot, short-lived star that generates an intense stellar wind. In fact, Wolf-Rayet stars are known to create nebulae with interesting shapes as their powerful winds sweep up surrounding interstellar material. In this case, the bright edge was thought to indicate a bow shock produced as the star plowed through a uniform medium, like a boat through water. But measurements have shown the star is not really moving directly toward the bright edge. So a more likely explanation is that the material surrounding the star is not uniform, but clumped and denser near the bright edge of windblown NGC 3199. via NASA https://ift.tt/3nQ2kKB

What creates STEVEs? Strong Thermal Emission Velocity Enhancements (STEVEs) have likely been seen since antiquity, but only in the past five years has it been realized that their colors and shapes make them different from auroras. Seen as single bright streaks of pink and purple, the origin of STEVEs remain an active topic of research. STEVEs may be related to subauroral ion drifts (SAIDs), a supersonic river of hot atmospheric ions. For reasons currently unknown, STEVEs are frequently accompanied by green « picket-fence » auroras. The featured STEVE image is a combination of foreground and background exposures taken consecutively in mid-March from Copper Harbor, Michigan, USA. This bright STEVE lasted several minutes, spanned from horizon to horizon, and appeared in between times of normal auroras. via NASA https://ift.tt/33dti5i

That’s no sunspot. It’s the International Space Station (ISS) caught passing in front of the Sun. Sunspots, individually, have a dark central umbra, a lighter surrounding penumbra, and no Dragon capsules attached. By contrast, the ISS is a complex and multi-spired mechanism, one of the largest and most complicated spacecraft ever created by humanity. Also, sunspots circle the Sun, whereas the ISS orbits the Earth. Transiting the Sun is not very unusual for the ISS, which orbits the Earth about every 90 minutes, but getting one’s location, timing and equipment just right for a great image is rare. The featured picture combined three images all taken from the same location and at nearly the same time. One image — overexposed — captured the faint prominences seen across the top of the Sun, a second image — underexposed — captured the complex texture of the Sun’s chromosphere, while the third image — the hardest to get — captured the space station as it shot across the Sun in a fraction of a second. Close inspection of the space station’s silhouette even reveals a docked Dragon Crew capsule. via NASA https://ift.tt/33bXUnF

After the most famous voyage of modern times, it was time to go home. After proving that humanity has the ability to go beyond the confines of planet Earth, the first humans to walk on another world — Neil Armstrong and Buzz Aldrin — flew the ascent stage of their Lunar Module back to meet Michael Collins in the moon-orbiting Command and Service Module. Pictured here on 1969 July 21 and recently digitally restored, the ascending spaceship was captured by Collins making its approach, with the Moon below, and Earth far in the distance. The smooth, dark area on the lunar surface is Mare Smythii located just below the equator on the extreme eastern edge of the Moon’s near side. It is said of this iconic image that every person but one was in front of the camera. via NASA https://ift.tt/2RnvuEv

What forms lurk in the mists of the Carina Nebula? The dark ominous figures are actually molecular clouds, knots of molecular gas and dust so thick they have become opaque. In comparison, however, these clouds are typically much less dense than Earth’s atmosphere. Featured here is a detailed image of the core of the Carina Nebula, a part where both dark and colorful clouds of gas and dust are particularly prominent. The image was captured in mid-2016 from Siding Spring Observatory in Australia. Although the nebula is predominantly composed of hydrogen gas — here colored green, the image was assigned colors so that light emitted by trace amounts of sulfur and oxygen appear red and blue, respectively. The entire Carina Nebula, cataloged as NGC 3372, spans over 300 light years and lies about 7,500 light-years away in the constellation of Carina. Eta Carinae, the most energetic star in the nebula, was one of the brightest stars in the sky in the 1830s, but then faded dramatically. via NASA https://ift.tt/3xAJKe1