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May 20 in spaceflight
Wikipedia records 7 spaceflight and astronomy events on May 20. Below are the pictures NASA published on May 20 in 6 different years — each one taken or released on this exact date.
Recorded events
IN THE RECORD7ENTRIES
Spaceflight and astronomy entries from Wikipedia's record of this date, oldest first — from 1217 onward.
Pictures from this date
PUBLISHED6IMAGES
NASA's Astronomy Picture of the Day for May 20, one per year. Some are public domain and some belong to the photographer — each says which.
Published on May 20
NASA’s Astronomy Picture of the Day, for this calendar date in each of the last several years.
2026
The Dark Wolf Nebula
A dark wolf lies in gum. No, this isn’t a riddle! Today's image features the Dark Wolf Nebula (Sandqvist–Lindroos 17), a spooky dust cloud embedded within the Gum 55 (RCW 113) Nebula in the Scorpius constellation. While dust is a pest to us, it serves a vital role in creating the necessary conditions for stars to be born. The Dark Wolf absorbs the intense ultraviolet and visible light emitted by young stars in Gum 55 and re-emits it at longer, mainly infrared, wavelengths. This prevents the higher energy light from heating up the gas in the region. When a region of gas is cool enough, gravity takes over and causes the gas to collapse into a star. Not only does dust act as an interstellar thermostat, but it is also the meet-cute for single hydrogen atoms forming molecular hydrogen, the building block for stars. The seemingly sinister Dark Wolf is actually a harbinger of cosmic life.
© William Vrbasso Text: Keighley Rockcliffe (NASA GSFC, UMBC CSST, CRESST II) — used with the credit NASA publishes
2025
Milky Way over Maunakea
Have you ever seen the band of our Milky Way Galaxy? In a clear sky from a dark location at the right time, a faint band of light becomes visible across the sky. Soon after your eyes become dark adapted, you might spot the band for the first time. It may then become obvious. Then spectacular. One reason for your growing astonishment might be the realization that this fuzzy swath, the Milky Way, contains billions of stars. Visible in the featured image, high above in the night sky, the band of the Milky Way Galaxy arcs. Also visible are the colorful clouds of Rho Ophiuchi on the right, and the red and circular Zeta Ophiuchi nebula near the top center. Taken in late February from Maunakea, Hawaii, USA, the foreground telescope is the University of Hawaii's 2.2-Meter Telescope. Fortunately, you don’t need to be near the top of a Hawaiian volcano to see the Milky Way. Put it All Together: Astronomy Puzzle of the Day
© Marzena Rogozinska — used with the credit NASA publishes
2024
Aurora Dome Sky
It seemed like night, but part of the sky glowed purple. It was the now famous night of May 10, 2024, when people over much of the world reported beautiful aurora-filled skies. The featured image was captured this night during early morning hours from Arlington, Wisconsin, USA. The panorama is a composite of several 6-second exposures covering two thirds of the visible sky, with north in the center, and processed to heighten the colors and remove electrical wires. The photographer (in the foreground) reported that the aurora appeared to flow from a point overhead but illuminated the sky only toward the north. The aurora's energetic particles originated from CMEs ejected from our Sun over sunspot AR 3664 a few days before. This large active region rotated to the far side of the Sun last week, but may well survive to rotate back toward the Earth next week.
© Xuecheng Liu & Yuxuan Liu — used with the credit NASA publishes
2023
Galileo's Europa
Looping through the Jovian system in the late 1990s, the Galileo spacecraft recorded stunning views of Europa and uncovered evidence that the moon's icy surface likely hides a deep, global ocean. Galileo's Europa image data has been remastered here, with improved calibrations to produce a color image approximating what the human eye might see. Europa's long curving fractures hint at the subsurface liquid water. The tidal flexing the large moon experiences in its elliptical orbit around Jupiter supplies the energy to keep the ocean liquid. But more tantalizing is the possibility that even in the absence of sunlight that process could also supply the energy to support life, making Europa one of the best places to look for life beyond Earth. What kind of life could thrive in a deep, dark, subsurface ocean? Consider planet Earth's own extreme shrimp.
NASA · public domain
2022
A View from Earth's Shadow
This serene sand and skyscape finds the Dune of Pilat on the coast of France still in Earth's shadow during the early morning hours of May 16. Extending into space, the planet's dark umbral shadow covered the Moon on that date. From that location the total phase of a lunar eclipse had begun before moonset. Still in sunlight though, the International Space Station crossed from the western horizon and Earth's largest artificial moon traced the bright flat arc through the sky over 400 km above. Simply constructed, the well-planned panoramic scene was captured over a 5 minutes in a series of consecutive images.
© Maxime Oudoux — used with the credit NASA publishes
2021
M13: The Great Globular Cluster in Hercules
In 1716, English astronomer Edmond Halley noted, "This is but a little Patch, but it shews itself to the naked Eye, when the Sky is serene and the Moon absent." Of course, M13 is now less modestly recognized as the Great Globular Cluster in Hercules, one of the brightest globular star clusters in the northern sky. Sharp telescopic views like this one reveal the spectacular cluster's hundreds of thousands of stars. At a distance of 25,000 light-years, the cluster stars crowd into a region 150 light-years in diameter. Approaching the cluster core upwards of 100 stars could be contained in a cube just 3 light-years on a side. For comparison, the closest star to the Sun is over 4 light-years away. The remarkable range of brightness recorded in this image follows stars into the dense cluster core. Distant background galaxies in the medium-wide field of view include NGC 6207 at the lower right.
© Martin Dufour — used with the credit NASA publishes
What happened on May 20
1217
First Barons' War: English forces under William Marshal defeated French troops at the Battle of Lincoln.
First Barons' War ↗
1217
The Second Battle of Lincoln is fought near Lincoln, England, resulting in the defeat of Prince Louis of France by William Marshal, 1st Earl of Pembroke.
Battle of Lincoln (1217) ↗
1570
Cartographer Abraham Ortelius issues Theatrum Orbis Terrarum, the first modern atlas.
Cartography ↗1811
A British squadron under Charles Marsh Schomberg defeated a French force off Tamatave, Madagascar, that was attempting to reinforce the French garrison on Mauritius.
Charles Marsh Schomberg ↗
1932
Amelia Earhart takes off from Newfoundland to begin the world's first solo nonstop flight across the Atlantic Ocean by a female pilot, landing in Ireland the next day.
Amelia Earhart ↗
1956
In Operation Redwing, the first United States airborne hydrogen bomb is dropped over Bikini Atoll in the Pacific Ocean.
Operation Redwing ↗
1964
Discovery of the cosmic microwave background radiation by Robert Woodrow Wilson and Arno Penzias.
Discovery of cosmic microwave background radiation ↗
Sources and licences
Event text and thumbnails come from Wikipedia and are used under CC BY-SA 4.0. Images are drawn only from Wikimedia Commons, which does not accept non-free content — each thumbnail links to its file page, where its licence and author are recorded.
Launch records are from The Space Devs’ Launch Library 2. This archive is still being mirrored, so some days are incomplete. Pictures are NASA’s Astronomy Picture of the Day; NASA imagery is generally not subject to copyright, but individual APOD entries are frequently the property of the photographer, and each caption says which applies.
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Cosmos — Carl Sagan
Still the best single argument for why any of this matters, and it leaves the arithmetic in. For a reader who wants the science, not just the awe.
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Pale Blue Dot — Carl Sagan
The case for leaving Earth, written by someone unsentimental about how hard that is. Suits readers who want the argument rather than the poster.
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Project Hail Mary — Andy Weir
Hard-SF problem solving in The Martian's key — for anyone who liked the engineering more than the peril. The only novel on this list.
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