On the upper right, dressed in blue, is the Pleiades. Also known as the Seven Sisters and M45, the Pleiades is one of the brightest and most easily visible open clusters on the sky. The Pleiades contains over 3,000 stars, is about 400 light years away, and only 13 light years across. Surrounding the stars is a spectacular blue reflection nebula made of fine dust. A common legend is that one of the brighter stars faded since the cluster was named. On the lower left, shining in red, is the California Nebula. Named for its shape, the California Nebula is much dimmer and hence harder to see than the Pleiades. Also known as NGC 1499, this mass of red glowing hydrogen gas is about 1,500 light years away. Although about 25 full moons could fit between them, the featured wide angle, deep field image composite has captured them both. A careful inspection of the deep image will also reveal the star forming region IC 348 and the molecular cloud LBN 777 (the Baby Eagle Nebula). via NASA https://ift.tt/SrBnDG3

No, the car was not in danger of being vacuumed into space by the big sky vortex. For one reason, the vortex was really an aurora, and since auroras are created by particles striking the Earth from space, they do not create a vacuum. This rapidly developing auroral display was caused by a Coronal Mass Ejection from the Sun that passed by the Earth closely enough to cause a ripple in Earth’s magnetosphere. The upper red parts of the aurora occur over 250 kilometers high with its red glow created by atmospheric atomic oxygen directly energized by incoming particles. The lower green parts of the aurora occur over 100 kilometers high with its green glow created by atmospheric atomic oxygen energized indirectly by collisions with first-energized molecular nitrogen. Below 100 kilometers, there is little atomic oxygen, which is why auroras end abruptly. The concentric cylinders depict a dramatic auroral corona as seen from the side. The featured image was created from a single 3-second exposure taken in mid-March over Lake Myvatn in Iceland. via NASA https://ift.tt/Ss83RlN

Our Earth is not at rest. The Earth moves around the Sun. The Sun orbits the center of the Milky Way Galaxy. The Milky Way Galaxy orbits in the Local Group of Galaxies. The Local Group falls toward the Virgo Cluster of Galaxies. But these speeds are less than the speed that all of these objects together move relative to the cosmic microwave background radiation (CMBR). In the featured all-sky map from the COBE satellite in 1993, microwave light in the Earth’s direction of motion appears blueshifted and hence hotter, while microwave light on the opposite side of the sky is redshifted and colder. The map indicates that the Local Group moves at about 600 kilometers per second relative to this primordial radiation. This high speed was initially unexpected and its magnitude is still unexplained. Why are we moving so fast? What is out there? via NASA https://ift.tt/kCVHx2P

This almost otherworldly display of northern lights was captured in clear skies during the early hours of March 31 from 44 degrees north latitude, planet Earth. In a five second exposure the scene looks north from Martinique Beach Provincial Park in Nova Scotia, Canada. Stars of the W-shaped constellation Cassiopeia shine well above the horizon, through the red tint of the higher altitude auroral glow. Auroral activity was anticipated by skywatchers alerted to the possibility of stormy space weather by Sun-staring spacecraft. The predicted geomagnetic storm was sparked as a coronal mass ejection, launched from prolific solar active region 2975, impacted our fair planet’s magnetosphere. via NASA https://ift.tt/4V0rNlv

The natural filter of a hazy atmosphere offered this recognizable architecture and sunset view on March 27. Dark against the solar disk, large sunspots in solar active regions 2975 and 2976 are wedged between the Duomo of Pisa and its famous Leaning Tower. Only one day later, Sun-staring spacecraft watched active region 2975 unleash a frenzy of solar flares along with two coronal mass ejections. The largest impacted the magnetosphere on March 31 triggering a geomagnetic storm and aurorae in high-latitude night skies. On March 30, active region 2975 erupted again with a powerful X-class solar flare that caused a temporary radio blackout on planet Earth. via NASA https://ift.tt/BVAjD4T

Some 60 million light-years away in the southerly constellation Corvus, two large galaxies are colliding. Stars in the two galaxies, cataloged as NGC 4038 and NGC 4039, very rarely collide in the course of the ponderous cataclysm that lasts for hundreds of millions of years. But the galaxies’ large clouds of molecular gas and dust often do, triggering furious episodes of star formation near the center of the cosmic wreckage. Spanning over 500 thousand light-years, this stunning view also reveals new star clusters and matter flung far from the scene of the accident by gravitational tidal forces. The remarkably sharp ground-based image, an accumulation of 88 hours of exposure captured during 2012-2021, follows the faint tidal tails and distant background galaxies in the field of view. The suggestive overall visual appearance of the extended arcing structures gives the galaxy pair, also known as Arp 244, its popular name – The Antennae. via NASA https://ift.tt/QUdrJ1a

What do you call a cosmic puzzle that no one expected to see? In this case, Odd Radio Circles, aka ORCs. ORC-1 typifies the enigmatic five objects, only visible at radio frequencies, that were serendipitously discovered in 2019 using the new Australian SKA Pathfinder radio array. The final image in the featured video uses 2021 data from the South African MeerKAT array to reveal more detail. The radio data, assigned turquoise colors, are combined with a Dark Energy Survey optical/IR map. The animated artist’s illustration explores just one idea about the ORCs’ origins. If two supermassive black holes merge in the center of a galaxy, the associated shockwaves could generate rings of radio radiation. These grow to fill the video frame. The video zooms out so the expansion the ORC can be tracked until it is about a million light-years across. Fortunately, the up-coming Square Kilometer Array can help test this and other promising scenarios. via NASA https://ift.tt/h1R8Atk

When two planets pass on the night sky, they can usually be seen near each other for a week or more. In the case of this planetary conjunction, Venus and Mars passed within 4 degrees of each other earlier this month. The featured image was taken a few days prior, when Venus was slowing rising in the pre-dawn sky, night by night, while Mars was slowly setting. The image, a four-part mosaic, was captured in Brazil from the small town Teresópolis. Besides Venus and Mars, the morning sky now also includes the more distant planet Saturn. Of course, these conjunctions are only angular — Venus, Mars, and Saturn continue to orbit the Sun in very different parts of our Solar System. Next week, the angle between Saturn and Mars will drop to below a quarter of a degree. via NASA https://ift.tt/1sC0AOr

The southernmost part of the Milky Way contains not only the stars of the Southern Cross, but the closest star system to our Sun — Alpha Centauri. The Southern Cross itself is topped by the bright, yellowish star Gamma Crucis. A line from Gamma Crucis through the blue star at the bottom of the cross, Acrux, points toward the south celestial pole, located just above the small island in the featured picture — taken in early March. That island is Madivaru of the Maldives in the Indian Ocean. Against faint Milky Way starlight, the dark Coal Sack Nebula lies just left of the cross, while farther left along the Milky Way are the bright stars Alpha Centauri (left) and Beta Centauri (Hadar). Alpha Centauri A, a Sun-like star anchoring a three-star system with exoplanets, is a mere 4.3 light-years distant. Seen from Alpha Centauri, our own Sun would be a bright yellowish star in the otherwise recognizable constellation Cassiopeia. via NASA https://ift.tt/n0BFCMX

Why would the surface of Titan light up with a blinding flash? The reason: a sunglint from liquid seas. Saturn’s moon Titan has numerous smooth lakes of methane that, when the angle is right, reflect sunlight as if they were mirrors. Pictured here in false-color, the robotic Cassini spacecraft that orbited Saturn from 2004 to 2017 imaged the cloud-covered Titan in 2014 in different bands of cloud-piercing infrared light. This specular reflection was so bright it saturated one of Cassini’s infrared cameras. Although the sunglint was annoying — it was also useful. The reflecting regions confirm that northern Titan houses a wide and complex array of seas with a geometry that indicates periods of significant evaporation. During its numerous passes of our Solar System’s most mysterious moon, Cassini has revealed Titan to be a world with active weather — including times when it rains a liquefied version of natural gas. via NASA https://ift.tt/SaREW8b