Zooming in on Star Cluster Terzan 5 Zooming in on Star Cluster Terzan 5

Globular clusters once ruled the Milky Way. Back in the old days, back when our Galaxy first formed, perhaps thousands of globular clusters roamed our Galaxy. Today, there are less than 200 left. Over the eons, many globular clusters were destroyed by repeated fateful encounters with each other or the Galactic center. Surviving relics are older than any Earth fossil, older than any other structures in our Galaxy, and limit the universe itself in raw age. There are few, if any, young globular clusters in our Milky Way Galaxy because conditions are not ripe for more to form. The featured video shows what it might look like to go from the Earth to the globular cluster Terzan 5, ending with a picture of the cluster taken with the Hubble Space Telescope. This star cluster has been found to contain not only stars formed in the early days of our Milky Way Galaxy, but also, quite surprisingly, others that formed in a separate burst of star formation about 7 billion years later. via NASA https://ift.tt/2TRMxPD

Four Towers and the Equinox Moon Four Towers and the Equinox Moon

The first Full Moon of northern spring rises behind four distant towers in this telescopic view. In an image captured from some 40 kilometers west of the city of Madrid, this moonrise also represents a near coincidence of the full lunar phase with lunar perigee and the March equinox. Close to the horizon, the Full Moon's strangely rippled and distorted shape has more to do with the long sight-line through a layered atmosphere, though. Tantalizing visible effects of the substantial atmospheric refraction include the appearance of a thin floating sliver just above the lunar disk. The remarkable optical mirage is related to the more commonly witnessed green flash of the setting Sun. via NASA https://ift.tt/2U943Ow

A Symphony in Northern Winter Skies A Symphony in Northern Winter Skies

Despite the cold, a chance to view the shimmering northern lights coaxed this skygazer onto the frozen surface of Lake Superior on the west coast of the Keweenaw Peninusla and offered this nocturnal crescendo as a reward. A northern late winter night sky also plays across the panoramic composition of images made between 10pm and 1am on the night of February 28/March 1. At left, a faint band of Zodiacal light rises sharply from the horizon crossing Mars and the Pleides star cluster. Both the distant galaxy M31 and our own Milky Way shine above the greenish auroral arc. Navigational north pole star Polaris is centered above and accompanied on the right by the northern night's most recognizable asterism, the Big Dipper. Terrestrial lights include markers for two breakwaters on the the horizon near the center of the scene. via NASA https://ift.tt/2FrNgOu

Star Trails and the Equinox Sunrise Star Trails and the Equinox Sunrise

Stars trail and the Sun rises in this night and day composite panorama made on March 19. The view looks toward the eastern horizon from La Nava de Santiago, Spain. To create it, a continuous series of digital frames was recorded for about two hours and combined to trace the concentric motion of the stars through the night sky. A reflection of the Earth's rotation, star trails curve around the north celestial pole toward upper left and the south celestial pole toward the lower right. Of course on that day the Sun was near the celestial equator, a diagonal straight line in the wide-angle projection. A dense dimming filter was used to capture the Sun's image every two minutes. Superimposed on the star trails it rose due east in the morning sky. In the scene, foreground landscape and a local prehistoric monument were illuminated by full moonlight, though. The monument's corridor faces nearly to the east and the equinox sunrise. via NASA https://ift.tt/2WaUxrz

Equinox on Planet Earth Equinox on Planet Earth

Welcome to an equinox on planet Earth. Today is the first day of spring in our fair planet's northern hemisphere, fall in the southern hemisphere, with day and night nearly equal around the globe. At an equinox Earth's terminator, the dividing line between day and night, connects the planet's north and south poles as seen at the start of this remarkable time-lapse video compressing an entire year into twelve seconds. To make it, the Meteosat satellite recorded these infrared images every day at the same local time from a geosynchronous orbit. The video actually starts at the September 2010 equinox with the terminator aligned vertically. As the Earth revolves around the Sun, the terminator tilts to provide less daily sunlight to the northern hemisphere, reaching the solstice and northern hemisphere winter at the maximum tilt. As the year continues, the terminator tilts back again and March 2011 equinox arrives halfway through the video. Then the terminator swings past vertical the other way, reaching the the June 2011 solstice and the beginning of northern summer. The video ends as the September equinox returns. via NASA https://ift.tt/2Joytbm

Abell 370: Galaxy Cluster Gravitational Lens Abell 370: Galaxy Cluster Gravitational Lens

What are those strange arcs? While imaging the cluster of galaxies Abell 370, astronomers noticed an unusual arc. The arc wasn't understood right away -- not until better images showed that the arc was a previously unseen type of astrophysical artifact of a gravitational lens, where the lens was the center of an entire cluster of galaxies. Today, we know that this arc, the brightest arc in the cluster, actually consists of two distorted images of a fairly normal galaxy that happens to lie far in the distance. Abell 370's gravity caused the background galaxies' light -- and others -- to spread out and come to the observer along multiple paths, not unlike a distant light appears through the stem of a wine glass. Almost all of the yellow images featured here are galaxies in the Abell 370 cluster. An astute eye can pick up many strange arcs and distorted arclets, however, that are actually gravitationally lensed images of distant normal galaxies. Studying Abell 370 and its images gives astronomers a unique window into the distribution of normal and dark matter in galaxy clusters and the universe. via NASA https://ift.tt/2Tcf90R

Horsehead and Orion Nebulas Horsehead and Orion Nebulas

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 two-panel mosaic. The familiar Horsehead nebula appears as a dark cloud on the lower left, a small silhouette notched against the glow of hydrogen (alpha) gas, here tinted orange. Alnitak is the easternmost star in Orion's belt and can be found 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, surrounded by the blue glow of reflecting dust. 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/2Y4gWIX

M106: A Spiral Galaxy with a Strange Center M106: A Spiral Galaxy with a Strange Center

What's happening at the center of spiral galaxy M106? A swirling disk of stars and gas, M106's appearance is dominated by blue spiral arms and red dust lanes near the nucleus, as shown in the featured image. The core of M106 glows brightly in radio waves and X-rays where twin jets have been found running the length of the galaxy. An unusual central glow makes M106 one of the closest examples of the Seyfert class of galaxies, where vast amounts of glowing gas are thought to be falling into a central massive black hole. M106, also designated NGC 4258, is a relatively close 23.5 million light years away, spans 60 thousand light years across, and can be seen with a small telescope towards the constellation of the Hunting Dogs (Canes Venatici). via NASA https://ift.tt/2Jhrdhr

Perseverance Valley Panorama Perseverance Valley Panorama

Mars exploration rover Opportunity's parting panorama from Perseverance Valley spans 360 degrees in this false color mosaic. The scene is composed of 354 individual images recorded through 3 different color filters by the rover's panoramic camera from May 13 through June 10, 2018. A few frames remain in black and white at the lower left though. Those were obtained through only one filter just before a dust storm engulfed Mars in June 2018, ultimately ending the solar-powered rover's trailblazing 15 year mission. Just right of center, the annotation identifies Opportunity's entry point to Perseverance Valley along the Endeavor crater's western rim. The rover's tracks begin there, extending from over the horizon toward the far right and its final resting spot on the Red Planet. via NASA https://ift.tt/2F42VSX

Highlights of the North Spring Sky Highlights of the North Spring Sky

What can you see in the night sky this season? The featured graphic gives a few highlights for Earth's northern hemisphere. Viewed as a clock face centered at the bottom, early (northern) spring sky events fan out toward the left, while late spring events are projected toward the right. Objects relatively close to Earth are illustrated, in general, as nearer to the cartoon figure with the telescope at the bottom center -- although almost everything pictured can be seen without a telescope. As happens during any season, constellations appear the same year to year, and, as usual, the Lyrids meteor shower will peak in mid-April. Also as usual, the International Space Station (ISS) can be seen, at times, as a bright spot drifting across the sky after sunset. After the Vernal Equinox next week, the length of daytime will be greater than the length of nighttime in Earth's northern hemisphere, an inequality that will escalate as the spring season develops. Also as spring ages, Jupiter becomes visible increasingly earlier in the night. As spring draws to a close, the month of May will feature two full moons, the second of which is called a Blue Moon. via NASA https://ift.tt/2HfNMBA