Uploaded January 2010 | Updated September 2026, 1 week ago

---

Science & Reason on Facebook: tinyurl.com/ScienceReason

NASA Astronomy Pictures Of The Day [Week 1/2010].

---
Please subscribe to Science & Reason:
• youtube.com/Best0fScience
• youtube.com/ScienceMagazine
• youtube.com/ScienceTV
• youtube.com/FFreeThinker
---

► A Roll Cloud Over Uruguay
These rare long clouds may form near advancing cold fronts. In particular, a downdraft from an advancing storm front can cause moist warm air to rise, cool below its dew point, and so form a cloud. When this happens uniformly along an extended front, a roll cloud may form. Roll clouds may actually have air circulating along the long horizontal axis of the cloud. A roll cloud is not thought to be able to morph into a tornado.
• Learn more: antwrp.gsfc.nasa.gov/apod/ap100105.html

► The Spotty Surface of Betelgeuse
Betelgeuse really is a big star. If placed at the center of our Solar System it would extend to the orbit of Jupiter. But like all stars except the Sun, the red supergiant is so distant it usually appears as a single point of light, even in large telescopes. The intriguing picture shows two, large, bright, star spots. The spots potentially represent enormous convective cells rising from below the supergiant's surface. They are bright because they're hotter than the rest of the surface, but both spots and surface are cooler than the Sun. Betelgeuse is about 600 light-years away.
• Learn more: antwrp.gsfc.nasa.gov/apod/ap100106.html

► The Tail of the Small Magellanic Cloud
A satellite galaxy of our Milky Way, the Small Magellanic Cloud is wonder of the southern sky, named for 16th century Portuguese circumnavigator Ferdinand Magellan. Some 200,000 light-years distant in the constellation Tucana, the small irregular galaxy's stars, gas, and dust that lie along a bar and extended "wing", are familiar in images from optical telescopes.
• Learn more: antwrp.gsfc.nasa.gov/apod/ap100107.html

► Andromeda Island Universe
The most distant object easily visible to the eye is M31, the great Andromeda Galaxy some two and a half million light-years away. But without a telescope, even this immense spiral galaxy - spanning over 200,000 light years - appears as a faint, nebulous cloud in the constellation Andromeda. In contrast, details of a bright yellow nucleus and dark winding dust lanes, are revealed in this digital telescopic image. Were these "spiral nebulae" simply outlying components of our own Milky Way Galaxy or were they instead "island universes" -- distant systems of stars comparable to the Milky Way itself?
• Learn more: antwrp.gsfc.nasa.gov/apod/ap100109.html

► The Mystery of the Fading Star
Every 27 years Epsilon Aurigae fades, remaining dim for roughly two years before growing bright again. Since the 19th century, astronomers have studied the mystery star, eventually arguing that Epsilon Aur, centered in this telescopic skyview, was actually undergoing a long eclipse by a dark companion object. But the nature of the companion and even the state of bright star itself could not be pinned down by observations.
• Learn more: antwrp.gsfc.nasa.gov/apod/ap100108.html

► A Spherule from the Earth's Moon
How did this spherule come to be on the Moon? When a meteorite strikes the Moon, the energy of the impact melts some of the splattering rock, a fraction of which might cool into tiny glass beads. Many of these glass beads were present in lunar soil samples returned to Earth by the Apollo missions.
• Learn more: antwrp.gsfc.nasa.gov/apod/ap100110.html

► Blue Moon Eclipse
The International Year of Astronomy 2009 ended with a Blue Moon and a partial lunar eclipse, as the second Full Moon of December grazed the Earth's shadow on December 31st.
• Learn more: antwrp.gsfc.nasa.gov/apod/ap100102.html

► The Astronaut Who Captured a Satellite
In 1984, high above the Earth's surface, an astronaut captured a satellite. It was the second satellite captured that mission.
• Learn more: antwrp.gsfc.nasa.gov/apod/astropix.html
.