Astronomy Picture of the Day [ko]

Moons, Rings, Shadows, Clouds: Saturn (Cassini)

2026-06-16T03:00:00+00:00

Explanation: While cruising around Saturn, be on the lookout for picturesque arrangements of moons, rings, and shadows. One such striking sight occurred in 2005 and was captured by the then Saturn-orbiting Cassini spacecraft. In the featured image, moons Mimas (left) and Tethys (right) are visible on either side of Saturn's thin rings, which are seen nearly edge-on. Across the top of Saturn are dark shadows of the wide rings, exhibiting their impressive complexity. The violet-light image brings up the texture of the backdrop: Saturn's clouds. Cassini orbited Saturn from 2004 until mid-2017, when the robotic spacecraft was directed to dive into Saturn to keep it from contaminating any moons.

Triple Shockwave from Sun Crossing Rocket

2026-06-15T03:00:00+00:00

Explanation: What's happening to this Sun-crossing rocket? The SpaceX Falcon 9 rocket, visible on the upper left, launched only about one minute before this amazing image was captured. As it rose to low Earth orbit from Cape Canaveral, Florida, USA, in late May, the rocket became supersonic before it crossed the disk of the distant Sun -- from the perspective of the well-placed photographer. The spacecraft's high speed caused bow-shaped compressed-air shockwaves to form across leading surfaces, with at least three visible even outside the Sun's disk because they refract sunlight. The trailing exhaust caused turbulence visible on the lower right. None of this was damaging to the robotic Starlink 10-53 mission, which delivered 29 communications satellites to low Earth orbit as planned. And if that isn't amazing enough - the Sun had spots!

10 Days of Venus and Jupiter

2026-06-14T03:00:00+00:00

Explanation: Venus and Jupiter may have caught your attention lately. The recent close conjunction of the two brightest planets in recent evening skies has been hard to miss. With Jupiter at the top, starting on May 30 and ending on June 8, their close approach was chronicled daily, left to right, in the featured panels from Maharashtra, India. Near the western horizon, the evening sky colors and exposures used for each panel depend on the local conditions near sunset. At their closest on June 9, the celestial pair appeared to be only about three times the width of a full moon apart. Of course, on that date, the two planets were physically separated by over 600 million kilometers in their orbits around the Sun. In the coming days, Jupiter will slowly settle into the sunset glare, but Venus will continue to move farther from the Sun in the western sky to excel in its current role as the brilliant evening star.

Interplanetary Earth

2026-06-13T03:00:00+00:00

Explanation: In an interplanetary first, on July 19, 2013 Earth was photographed on the same day from two other worlds of the Solar System, innermost planet Mercury and ringed gas giant Saturn. Pictured on the left, Earth is the pale blue dot just below the rings of Saturn, as captured by the robotic Cassini spacecraft then orbiting the outermost gas giant. On that same day people across planet Earth snapped many of their own pictures of Saturn. On the right, the Earth-Moon system is seen against the dark background of space as captured by the sunward MESSENGER spacecraft, then in Mercury orbit. MESSENGER took its image as part of a search for small natural satellites of Mercury, moons that would be expected to be quite dim. In the MESSENGER image, the brighter Earth and Moon are both overexposed and shine brightly with reflected sunlight. Destined not to return to their home world, both Cassini and MESSENGER have since retired from their missions of Solar System exploration.

Venus and Jupiter: Conjunction from Avebury

2026-06-12T03:00:00+00:00

Explanation: To see Venus and Jupiter together this month, you won't need binoculars or even a telescope. Just look up after sunset and you'll find them emerging as the sky grows dark near the western horizon. In fact, on June 9 the two brightest planets were in close conjunction, separated on the sky by less than 2 degrees from our perspective. Since (brighter) inner planet Venus orbits the Sun faster than outer planet Jupiter, it catches up with and passes the outer planet along the ecliptic roughly every 13 months. But every three years or so their resulting conjunction can be viewed far enough from the Sun to be easily seen in Earth's twilight skies. On June 9, the two celestial beacon's close "cosmic kiss" was captured here next to the two large standing stones at the cove within a 4,000 year old stone circle at Avebury, UK. Larger than Stonehenge, the Avebury henge and stone circle complex is also recognized as one of the most significant neolithic ceremonial sites on planet Earth.

The Mermaid Nebula Supernova Remnant

2026-06-11T03:00:00+00:00

Explanation: Could the Little Mermaid turn into stardust instead of seafoam? It would seem so in this beautiful nebula. The featured image shows the Mermaid Nebula, also known as the Betta Fish Nebula, which is part of the G296.5+10.0 Supernova Remnant. The blue color visible here originates from doubly ionized oxygen (OIII), while the deep red is emitted by hydrogen gas. Estimated to be located a few thousand light-years away and about 10,000 years old, this nebula was formed when a massive star exploded as a supernova. It left behind a peculiar pulsar, a young radio-quiet neutron star that spins around about twice every second. The bright stars shown in the image are unassociated with the nebula. The pulsar can be detected in the X-rays but it does not have a confirmed detection in the optical (visible light) so far. As a result, the pulsar itself is not visible in this image.

The Eagle Nebula and Friends

2026-06-10T03:00:00+00:00

Explanation: What looks as if it is going to swallow the great Pillars of Creation? The Eagle Nebula (M16) is not a bird, a plane, or Superman. M16 is actually a combination of several celestial objects. NGC 6611 is the young star cluster that appears to peak out beneath the Eagle’s “wings”. The ultraviolet light from these stars ionizes the surrounding gas, creating the emission nebula IC 4703. The Stellar Spire is seen reaching towards the Pillars of Creation from the left. Both are structures of cold gas and dust that are optimal for star formation. Some astronomers previously thought the Pillars of Creation had been evaporated away by a supernova. Because M16 is 6,000 light years away, we would not be able to see the Pillars’ destruction for thousands more years. However, there is no conclusive evidence of the theorized supernova, so the Pillars of Creation will likely continue to create stars for millions of years.