Is this a cosmic monster ready to devour an unsuspecting galaxy? Thankfully, that is not the case. The red “monster” shown in the featured image is Cometary Globule CG 4, 1,300 light-years away in the Constellation Puppis. CG 4 is a molecular cloud, where hydrogen becomes cold enough to form molecules that can be brought together by gravity to create stars. The shape of CG 4 resembles that of a comet, but its head is 1.5 light-year in diameter and its tail is 8 light-years long; for comparison, the distance from the Earth to the sun is only 8 light-minutes. Astronomers believe that the tail of a cometary globule could have been shaped by a nearby supernova explosion or by irradiation from hot, massive stars. Indeed, CG 4 and other nearby globules point away from the Vela Supernova Remnant, at the center of the Gum Nebula. The edge-on spiral galaxy, ESO 257-19, is more than a hundred million light-years beyond CG 4, and is completely safe from the “monster”.

Are lasers from giant telescopes being used to defend the Earth? No. Lasers shot from telescopes are now commonly used to help increase the accuracy of astronomical observations. In some directions, Earth atmosphere-induced fluctuations in starlight can indicate how the air mass over a telescope is changing, but in other directions, no bright star exists. In these directions, astronomers can create an artificial star with a laser. Subsequent observations of the artificial laser guide star can reveal information so detailed about the changing blurring effects of the Earth's atmosphere that much of it can be removed by rapidly flexing a telescope's mirror. Such adaptive optics techniques allow high-resolution ground-based observations of real stars, planets, and nebulas. Pictured here, telescopes at Paranal Observatory in Chile study a colorful sky filled with green airglow and the Magellanic Clouds on the left, red airglow on the right, and the majestic central band of our Milky Way Galaxy arching across the center.

What's going on inside the head of this nebula? Dubbed the Exposed Cranium Nebula for its similarity to the human brain, what created the nebula remains a mystery. One thought is that the Cranium Nebula, also known as PMR 1, is a planetary nebula surrounding a white dwarf star. In this mode, the outer atmosphere was expelled when the original Sun-like star ran out of central nuclear fuel and contracted. A competing thought is that the central star is much more massive, possibly a Wolf-Rayet star, that is ejecting gas and dust via turbulent stellar winds. Adding to the intrigue is the dark vertical central division and the thin outer gaseous shell. The featured image was taken by the Webb Space Telescope in mid- infrared light, while a second image, included as a rollover, is in near-infrared. Future observations may reveal if this brainy system will quietly just fade from view or, many years from now, suddenly erupt in a powerful supernova.

Yes, but can your tree do this? Pictured is a visual coincidence between the dark branches of a nearby tree and bright glow of a distant aurora. The beauty of the aurora -- combined with how it seemed to mimic a tree right nearby -- mesmerized the photographer to such a degree that he momentarily forgot to take pictures. When viewed at the right angle, it seemed that this tree had aurora for leaves. Fortunately, before the aurora morphed into a different overall shape, he came to his senses and captured the awe-inspiring momentary coincidence. Typically triggered by solar explosions, aurora are caused by high energy electrons impacting the Earth's atmosphere around 150 kilometers up. The unusual Earth-sky collaboration was witnessed in March of 2017 in Iceland. Sky Surprise: What picture did APOD feature on your birthday? (after 1995)

Centered on maximum eclipse, these two total lunar eclipse sequences look almost identical. Yet the one shown on top is composed of images recorded in February 2008, while at the bottom is the recent March 2026 total eclipse of the Moon. Why are they so similar? Because these two total lunar eclipses are from the same Saros cycle. The Saros cycle was discovered historically from observations of the Moon's orbit. With a period of 18 years, 11 and 1/3 days, the cycle predicts when the Sun, Earth, and Moon all return to the same relative geometry for a lunar (or solar) eclipse. Eclipses separated by one Saros period belong to the same numbered Saros series, in this case Saros 133. So expect the next lunar eclipse in Saros 133 to be a repeat of this year's March 3 eclipse. You can watch the next Saros 133 total lunar eclipse on March 13, 2044. Growing Gallery: Total Lunar Eclipse of March 3

Do young stars blow bubbles? The larger view shows a stellar field observed with the Cerro Tololo Inter-American Observatory in Chile, and the inset highlights HD 61005, a star like our Sun, only 120 light-years away. Much younger than the Sun, at just about 100 million years old, it blows a fast and dense stellar wind that pushes out the cooler dust and gas that surrounds it, forming a bubble called an astrosphere. The star-blown bubble was detected with the Chandra X-ray Observatory, and it has a diameter roughly 200 times the Earth-Sun distance. Our Sun has a bubble too, called the heliosphere, which protects the planets from cosmic radiation. Also shown in the inset is debris left behind from star formation, observed by Hubble. The debris appears as wings, giving the star its nickname: the Moth.

rlier this week, Earth’s shadow swept across the full Moon in the year’s only total lunar eclipse. This stunning sequence combines images showing the Moon’s path across the night sky. Each lunar image captures our planet’s shadow gradually engulfing the Moon, culminating in its red glow. Sunlight scatters and refracts as it passes through Earth’s atmosphere toward the Moon. Shorter wavelength light (blue and green) scatters more efficiently, leaving red, orange, and yellow hues to paint the lunar surface. Tsé Bit'a'í (”rock with wings”, also known as Shiprock), located in Navajo Nation, provides a powerful volcanic foreground central to this photo and to stories of Navajo origin, adventure, and heroism. As the first full moon of the lunar new year, this eclipse held significance across cultures. Visible from East Asia to North America, this eclipse united observers across great distances, a cosmic reminder that we share the same sky. Growing Gallery: Total Lunar Eclipse of March 3