Magazine Posts

NASA Astronomy Picture of the Day:

The Horsehead Nebula is one of the most famous nebulae on the sky. It is visible as the dark indentation to the red emission nebula in the center of the above photograph. The horse-head feature is dark because it is really an opaque dust cloud that lies in front of the bright red emission nebula. Like clouds in Earth's atmosphere, this cosmic cloud has assumed a recognizable shape by chance. After many thousands of years, the internal motions of the cloud will surely alter its appearance. The emission nebula's red color is caused by electrons recombining with protons to form hydrogen atoms. On the image left is the Flame Nebula, an orange-tinged nebula that also contains filaments of dark dust. Just to the lower left of the Horsehead nebula featured picture is a blueish reflection nebulae that preferentially reflects the blue light from nearby stars.

Photo by José Jiménez Priego

NASA Astronomy Picture of the Day:

After sunset on October 3, some of the Solar System's largest moons stood low along the western horizon with the largest planet. Just after nightfall, a pairing of the Moon approaching first quarter phase and Jupiter was captured in this telephoto field of view. A blend of short and long exposures, it reveals the familiar face of our fair planet's own large natural satellite in stark sunlight and faint earthshine. At lower right are the ruling gas giant and its four Galilean moons. Left to right, the tiny pinpricks of light are Ganymede, [Jupiter], Io, Europa, and Callisto. Our own natural satellite appears to loom large because it's close, but Ganymede, Io, and Callisto are actually larger than Earth's Moon. Water world Europa is only slightly smaller. Of the Solar System's six largest planetary satellites, only Saturn's moon Titan, is missing from this scene. But be sure to check for large moons in your sky tonight. Submitted to APOD: The Moon and Jupiter with its Satellites

Photo by Derek Demeter

NASA Astronomy Picture of the Day:

Clouds drift through the sky as the light fades near sunset in this three frame animated gif. The scene was captured on sol 145 beginning around 6:30pm local time by a camera on the Mars InSight lander. Of course, InSight's martian day, sol 145, corresponds to Earth calendar date April 25, 2019. Under the 69 centimeter (2.3 foot) diameter dome in the foreground is the lander's sensitive seismometer SEIS designed to detect marsquakes. Earthquakes reveal internal structures on planet Earth, and so tremors detected by SEIS can explore beneath the martian surface. In particular, two typical marsquakes were recorded by SEIS on May 22 (sol 173) and July 25 (sol 235). The subtle tremors from the Red Planet are at very low frequencies though, and for listening have to be processed into the audio frequency range. In the sped up recordings external noises more prevalent on cool martian evenings and likely caused by mechanical shifts and contractions have been technically dubbed dinks and donks.

NASA Astronomy Picture of the Day:

Gorgeous spiral galaxy M33 seems to have more than its fair share of glowing hydrogen gas. A prominent member of the local group of galaxies, M33 is also known as the Triangulum Galaxy and lies a mere 3 million light-years away. The galaxy's inner 30,000 light-years or so are shown in this magnificent 25 panel telescopic mosaic. Based on image data from space and ground-based telescopes, the portrait of M33 shows off the galaxy's reddish ionized hydrogen clouds or HII regions. Sprawling along loose spiral arms that wind toward the core, M33's giant HII regions are some of the largest known stellar nurseries, sites of the formation of short-lived but very massive stars. Intense ultraviolet radiation from the luminous, massive stars ionizes the surrounding hydrogen gas and ultimately produces the characteristic red glow. To enhance this image, broadband data was used to produce a color view of the galaxy and combined with narrowband data recorded through a hydrogen-alpha filter. That filter transmits the light of the strongest visible hydrogen emission line.

NASA Astronomy Picture of the Day:

They are not alive -- but they are dying. The unusual forms found in the Carina nebula, a few of which are featured here, might best be described as evaporating. Energetic light and winds from nearby stars are breaking apart the dark dust grains that make the iconic forms opaque. Ironically the figures, otherwise known as dark molecular clouds or bright rimmed globules, frequently create in their midst the very stars that later destroy them. The floating space structures pictured here by the orbiting Hubble Space Telescope span a few light months. The Great Nebula in Carina itself spans about 30 light years, lies about 7,500 light years away, and can be seen with a small telescope toward the constellation of Keel(Carina).

NASA Astronomy Picture of the Day:

An old Moon rose this morning, its waning sunlit crescent shining just above the eastern horizon before sunrise. But earthshine, light reflected from a bright planet Earth, lit the shadowed portion of the lunar disk and revealed most of a familiar lunar near side to early morning risers. In fact, a description of earthshine in terms of sunlight reflected by Earth's oceans illuminating the Moon's dark surface was written over 500 years ago by Leonardo da Vinci. One lunation ago this old Moon also rose above the eastern horizon. Its sunlit crescent and da Vinci glow were captured in stacked exposures from the Badain Jilin Desert of Inner Mongolia, China on August 29, 2019. This year marks the 500th anniversary of Leondardo da Vinci's death.

Photo by Likai Lin

https://apod.nasa.gov/apod/ap190925.html
Image Credit & Copyright: Yannick Akar

NASA Astronomy Picture of the Day:

These three bright nebulae are often featured on telescopic tours of the constellation Sagittarius and the crowded starfields of the central Milky Way. In fact, 18th century cosmic tourist Charles Messier cataloged two of them; M8, the large nebula just left of center, and colorful M20 on the top left. The third emission region includes NGC 6559 and can be found to the right of M8. All three are stellar nurseries about five thousand light-years or so distant. Over a hundred light-years across, the expansive M8 is also known as the Lagoon Nebula. M20's popular moniker is the Trifid. Glowing hydrogen gas creates the dominant red color of the emission nebulae. In striking contrast, blue hues in the Trifid are due to dust reflected starlight. Recently formed bright blue stars are visible nearby. The colorful composite skyscape was recorded in 2018 in Teide National Park in the Canary Islands, Spain.

Photo by Emilio Rivero Padilla

NASA Astronomy Picture of the Day:

These three bright nebulae are often featured on telescopic tours of the constellation Sagittarius and the crowded starfields of the central Milky Way. In fact, 18th century cosmic tourist Charles Messier cataloged two of them; M8, the large nebula just left of center, and colorful M20 on the top left. The third emission region includes NGC 6559 and can be found to the right of M8. All three are stellar nurseries about five thousand light-years or so distant. Over a hundred light-years across, the expansive M8 is also known as the Lagoon Nebula. M20's popular moniker is the Trifid. Glowing hydrogen gas creates the dominant red color of the emission nebulae. In striking contrast, blue hues in the Trifid are due to dust reflected starlight. Recently formed bright blue stars are visible nearby. The colorful composite skyscape was recorded in 2018 in Teide National Park in the Canary Islands, Spain.

Photo by Emilio Rivero Padilla

NASA Astronomy Picture of the Day:

This weekend, meteors will rain down near the peak of the annual Perseid Meteor Shower. Normally bright and colorful, the Perseid shower meteors are produced by dust swept up by planet Earth from the orbit of Comet Swift-Tuttle. They streak from a radiant in Perseus, above the horizon in clear predawn skies. Despite interfering light from August's waning gibbous moon, this year's Perseids will still be enjoyable, especially if you can find yourself in an open space, away from city lights, and in good company. Frames used in this composite view capture bright Perseid meteors from the 2016 meteor shower set against a starry background along the Milky Way, with even the faint Andromeda Galaxy just above center. In the foreground, astronomers of all ages have gathered on a hill above the Slovakian village of Vrchtepla.

Photo by Petr Horálek