Wednesday, November 20, 2024

APOD - Earthset from Orion

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2024 November 20
See Explanation.  Clicking on the picture will download  the highest resolution version available.

Earthset from Orion
Image Credit: NASA, Artemis 1

Explanation: Eight billion people are about to disappear in this snapshot from space taken on 2022 November 21. On the sixth day of the Artemis I mission, their home world is setting behind the Moon's bright edge as viewed by an external camera on the outbound Orion spacecraft. Orion was headed for a powered flyby that took it to within 130 kilometers of the lunar surface. Velocity gained in the flyby maneuver was used to reach a distant retrograde orbit around the Moon. That orbit is considered distant because it's another 92,000 kilometers beyond the Moon, and retrograde because the spacecraft orbited in the opposite direction of the Moon's orbit around planet Earth. Orion entered its distant retrograde orbit on November 25. Swinging around the Moon, Orion reached a maximum distance (just over 400,000 kilometers) from Earth on November 28, exceeding a record set by Apollo 13 for most distant spacecraft designed for human space exploration. The Artemis II mission, carrying 4 astronauts around the moon and back again, is scheduled to launch no earlier than September 2025.

Tomorrow's picture: pixels in space


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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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Tuesday, November 19, 2024

APOD - Undulatus Clouds over Las Campanas Observatory

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2024 November 19
A series of white parallel clouds are seen going off  into the distance in a background blue sky. In the foreground  is a hill with two domes at the top.   Please see the explanation for more detailed information.

Undulatus Clouds over Las Campanas Observatory
Image Credit & Copyright: Yuri Beletsky (Carnegie Las Campanas Observatory, TWAN); h/t: Alice Allen

Explanation: What's happening with these clouds? While it may seem that these long and thin clouds are pointing toward the top of a hill, and that maybe a world-famous observatory is located there, only part of that is true. In terms of clouds, the formation is a chance superposition of impressively periodic undulating air currents in Earth's lower atmosphere. Undulatus, a type of Asperitas cloud, form at the peaks where the air is cool enough to cause the condensation of opaque water droplets. The wide-angle nature of the panorama creates the illusion that the clouds converge over the hill. In terms of land, there really is a world-famous observatory at the top of that peak: the Carnegie Science's Las Campanas Observatory in the Atacama Desert of Chile. The two telescope domes visible are the 6.5-meter Magellan Telescopes. The featured coincidental vista was a surprise but was captured by the phone of a quick-thinking photographer in late September.

Your Sky Surprise: What picture did APOD feature on your birthday? (post 1995)
Tomorrow's picture: flight day 6


< | Archive | Submissions | Index | Search | Calendar | RSS | Education | About APOD | Discuss | >

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
NASA Official: Amber Straughn Specific rights apply.
NASA Web Privacy, Accessibility, Notices;
A service of: ASD at NASA / GSFC,
NASA Science Activation
& Michigan Tech. U.


This is an automated email. If you notice any problems, just send me a note at gtracy@gmail.com. You can add and remove email addresses to this distribution list here, https://apodemail.org.Unsubscribe