Magazine Posts

NASA Astronomy Picture of the Day:

A flying saucer from outer space crash-landed in the Utah desert after being tracked by radar and chased by helicopters. The year was 2004, and no space aliens were involved. The saucer, pictured here, was the Genesis sample return capsule, part of a human-made robot Genesis spaceship launched in 2001 by NASA itself to study the Sun. The unexpectedly hard landing at over 300 kilometers per hour occurred because the parachutes did not open as planned. The Genesis mission had been orbiting the Sun collecting solar wind particles that are usually deflected away by Earth's magnetic field. Despite the crash landing, many return samples remained in good enough condition to analyze. Genesis-related discoveries included new details about the composition of the Sun and how the abundance of some types of elements differ across the Solar System. These results have provided intriguing clues into details of how the Sun and planets formed billions of years ago. Almost Hyperspace: Random APOD Generator

NASA Astronomy Picture of the Day:

At sunset, an alignment of rainbow and mountain shadow was captured in this remarkable snapshot. The stunning view was recorded from a fire lookout on Smith Peak in the Plumas National Forest near Portola, California on July 13. Still, near sunset it's no accident that the majestic mountain shadow seems to point to the center of the graceful rainbow arc. Due to perspective and the long line of sight the mountain shadow naturally forms a tapering triangular shape, its apex positioned at the point opposite the Sun on the horizon. Following thunderstorms across the region, the rainbow arcs across the early evening sky, with its colorful and characteristic 42 degree arc formed as sunlight is refracted and reflected by the atmospheric water droplets. The geometric center of a rainbow arc lies at the antisolar point. And in this scene from the golden hour on planet Earth, that's also oposite the setting Sun along the distant horizon.

NASA Astronomy Picture of the Day:

Comet 10P/Tempel 2 orbits the Sun once every 5.4 years. Currently visible in binoculars or small telescopes toward the constellation Capricornus, the periodic comet is captured in this sharp telescopic image from July 11 sporting a bright nuclear region and pretty greenish coma. Remarkably, a thin dust trail, not a typical dust tail, is also seen extending both east and west of the Tempel 2 nucleus. Unlike a comet dust tail, which tends to temporarily fan out in a direction away from the Sun, this dust trail is due to the residual dust shed during many past orbits along this ancient periodic comet's orbital plane. In fact, Tempel 2's dust trail may get a little narrower and brighter from our perspective as Earth crosses through the comet's orbital plane on July 20. Comet 10P/Tempel 2 will reach a perihelion on August 2, and make its closest approach to Earth on August 3.

Photo by Dan Bartlett

NASA Astronomy Picture of the Day:

This sparkling, colorful gemstone is a spiral galaxy, NGC 300. It is one of the closest spiral galaxies to Earth, only about 6 million light-years away. But does it really look like this? Here is a more standard portrait of it. This unusual image combines the light from the stars and dust within the galaxy with the light from ionized clouds of interstellar gas shown in red (Sulphur), green (Hydrogen) and blue (Oxygen). Combining red and green light in different proportions makes yellow or orange light, most visible in the image. Light from other ionized gases is also at work in neon signs, fluorescent tubes and street lights. These massive clouds of ionized gas are typically created by young, massive stars that produce high-energy ultraviolet radiation capable of ionizing the gas. Massive stars are short-lived, compared with lighter stars like our sun, and explode as supernovas at the end of their lives. Some of the colorful clouds in the image could be hiding supernova remnants.

Photo by Team Ciel Austral Text: Cecilia Chirenti (NASA GSFC, UMCP, CRESST II)

NASA Astronomy Picture of the Day:

Is there an angry Sith using force lightning in the Tatacoa Desert? This is not science fiction, but a red sprite with multiple streamers! Ordinary lightning occurs when thundercloud particles collide, lose their electrons, and build up negative charge at the cloud bottom. The cloud’s negative charge repels negative charge deeper into the Earth, leaving Earth’s surface positively charged. The opposite charges attract, reaching towards each other and superheating the air into a white strike of plasma. Red sprites are millisecond events triggered by positive cloud-to-ground lightning. They extend up into the mesosphere where the air is too thin for thunder. Their red glow comes from heated molecular nitrogen. There are several potential causes for red sprites, including that the preceding positive lightning exposes the negatively charged cloud core to the positively charged upper atmosphere, allowing those charges to connect. NASA’s Juno has observed sprites on Jupiter, indicating that sprites occur on other planets!

Photo by Mario Vargas Text: Keighley Rockcliffe (NASA GSFC, UMBC CSST, CRESST II)

NASA Astronomy Picture of the Day:

Why is this asteroid a double? Earlier this month the Japanese robotic spacecraft Hayabusa2 shot past asteroid 98943 Torifune and captured pictures. Although previous observations from distant Earth indicated that Torifune was oblong, Hayabusa2 found that Torifune actually has two joined lobes. With a length of about four soccer fields, this space rock frequently comes near the Earth as it orbits the Sun, although it is not a threat. Besides the two lobes, Torifune shows many large boulders, but, surprisingly, no obvious craters, likely because its surface is a pile of rubble. Like asteroid Arrokoth, it appears that each lobe formed separately before colliding and becoming stuck together. Hayabusa2 famously encountered asteroid Ryugu in 2018, and now heads for an encounter in 2031 with 1998 KY26, a smaller asteroid that rotates unusually fast and might have reservoirs of ice.

Photo by JAXA, U. of Tokyo, Chiba Tech, Tokyo U. of Science, AIST, Paris Obs., IAC

NASA Astronomy Picture of the Day:

What do auroras look like from above? Behold! From the ground, auroras dance high above clouds, frequently causing spectacular displays. From space, they look a bit different. As the International Space Station (ISS) circles the Earth every 90 minutes, it sometimes sees auroras below that are active on the night side. A one-hour time-lapse video showing auroras from above was captured about two weeks ago from the orbiting ISS. The ISS -- and all objects in low Earth orbit -- will pass well above green auroras but just a bit above red glowing auroras. The auroras' electron and proton streams are too thin to be a danger to the ISS, just as clouds pose little danger to airplanes. From orbit, as magnetic fields change, auroras can appear to squiggle and crawl like giant snakes. The featured one-minute video was captured by French astronaut Sophie Adenot of the ISS Expedition 74 crew. Sky Surprise: What picture did APOD feature on your birthday? (after 1995)

Watch NASA's Astronomy Video of the Day

NASA Astronomy Picture of the Day:

What's happening to galaxy NGC 474? The multiple layers of emission appear strangely complex given the relatively featureless appearance of the elliptical galaxy in less deep images. The cause of the shells is a topic of research, but they are possibly tidal tails related to debris left over from absorbing numerous small galaxies in the past billion years. Alternatively, the shells may be like ripples in a pond, where the ongoing collision with the spiral galaxy just to the right of NGC 474 is causing density waves to ripple through the galactic giant. Regardless of the actual cause, the featured image dramatically highlights the increasing evidence that the halos of some elliptical galaxies are surprisingly complicated. Similarly, the halo of our own Milky Way Galaxy is one example of such unexpected intricacies. NGC 474 spans about 250,000 light years and lies about 100 million light years distant toward the constellation of the Fish (Pisces).

NASA Astronomy Picture of the Day:

Unlike most entries in Charles Messier's famous catalog of deep sky objects, M24 is not a bright galaxy, star cluster, or nebula. It's a gap in nearby, obscuring interstellar dust clouds that allows a view of the distant stars in the Sagittarius spiral arm of our Milky Way galaxy. Direct your gaze through this gap with binoculars or a small telescope and you are looking through a window over 300 light-years wide at stars some 10,000 light-years or more from Earth. Sometimes called the Small Sagittarius Star Cloud, M24's luminous stars stretch across this gorgeous interstellar scene. Spanning over four full moons on the sky toward the constellation Sagittarius, the telescopic field of view includes dark markings B92 and B93 near the center of M24, along with other clouds of dust and glowing nebulae toward the center of the Milky Way.

Photo by Chuck Ayoub

NASA Astronomy Picture of the Day:

The Mare Orientale, Latin for Eastern Sea, is one of the most striking large scale lunar features. The youngest of the large lunar impact basins it's very difficult to see from an earthbound perspective. Still, captured on July 7 during a period of favorable tilt, or libration of the lunar nearside, the Eastern Sea can be found at the upper right in this sharp telescopic view. In the image, the large lunar mare is extremely foreshortened and stretches along the Moon's western edge. Formed by the impact of an asteroid over 3 billion years ago and nearly 1000 kilometers across, the impact basin's concentric circular features are ripples in the lunar crust. But they are a little easier to spot in more direct images of the region taken from lunar orbit. So why is the Eastern Sea at the Moon's western edge? The Mare Orientale lunar feature was named before 1961. That's when the convention labeling east and west on lunar maps was reversed.

Photo by The Mare Orientale

NASA Astronomy Picture of the Day:

This Cosmic Bat wishes you a happy Summerween! This mid-year celebration of Halloween transcends hemispheres, even though summer in the Northern hemisphere is winter in the South. Contrary to its eery aura, the Cosmic Bat Nebula (LDN 43), not to be confused with the Bat Nebula (NGC 6995), is a vibrant birthplace for stars. A bit of young starlight peeks through the dense clouds of gas and dust that make up the Cosmic Bat’s 12 lightyear wingspan. The ultraviolet light from the young stars energizes the nebula’s hydrogen gas, causing it to glow an ominous red. The jet of glowing hydrogen gas emerging from the bat’s head hints at the star formation hidden within.

Photo by Humbert Cédric Text: Keighley Rockcliffe (NASA GSFC, UMBC CSST, CRESST II)

NASA Astronomy Picture of the Day:

Sometimes we can all use a little help from a friend. NASA's Neil Gehrels Swift Observatory needs a boost to stay in orbit after almost 22 years of service. This video shows an artist's visualization of the Swift Boost Mission: The Katalyst's LINK spacecraft was launched aboard a Northrop Grumman Pegasus XL rocket on July 3 and it is now en route to rendezvous with Swift and boost it to a higher orbit over the course of the next several months. This type of maneuver has never been attempted before. If successful, it will be the technology demonstration of a new key capability to extended the lifetime of spacecraft in low Earth orbit, whose orbits decay over time. Swift has an array of instruments that observe the most energetic explosions in the Universe in gamma-rays, X-rays and ultraviolet, and the unique ability to repoint in their direction within tens of seconds. Astronomers around the world, and indeed all fans of cosmic explosions, are anxiously hoping for a successful mission!

Watch NASA's Astronomy Video of the Day