File:61_Danae.gif · Wikimedia Commons · See Wikimedia Commons
Picture of the Day · NASA
Pathfinder on Mars
2026-07-04
On July 4th, 1997, using its own array of fireworks, a parachute, and a cocoon of airbags, the Mars Pathfinder spacecraft bounced like a giant beach ball at least 15 times before it came to rest on the surface of Mars at 10:07 AM Pacific Daylight Time. After its then novel airbag-assisted landing sequence was completed, Pathfinder transmitted this color mosaic to mission operators on Earth. In the scene from another world, the Mars Sojourner robot rover is visible in the foreground, crouched on top of the unfolded Pathfinder. About the size of a large house cat, the six-wheeled, solar-powered Sojourner became the first successful Martian rover. Surrounding Pathfinder are deflated airbags and the rock-strewn terrain of the Ares Vallis floodplain. In the distance Martian hills appear against a dusty brownish sky. The Pathfinder lander was subsequently renamed the Carl Sagan Memorial Station.
via NASA APOD
Key facts
- Discovered by
- H. Goldschmidt
- Discovery site
- Paris
- Discovery date
- 9 September 1860
- Pronunciation
- / ˈ d æ n eɪ . iː /
- Named after
- Danaë (Greek mythology)
- Alternative designations
- 1953 RL 1 · A917 SM
- Minor planet category
- main-belt · ( outer ) , background
- Adjectives
- Danaëan / d æ n eɪ ˈ iː ə n /
- Observation arc
- 151.67 yr (55,398 days)
- Aphelion
- 3.4798 AU
- Perihelion
- 2.4840 AU
- Semi major axis
- 2.9819 AU
- Orbital period sidereal
- 5.15 yr (1,881 days)
- Mean anomaly
- 157.11 °
- Mean motion
- 0° 11 29.04 / day
- Inclination
- 18.212°
- Longitude of ascending node
- 333.72°
- Argument of perihelion
- 12.695°
via Wikipedia infobox
~2 min read
Encyclopedic overview
61 Danaë (/ˈdæneɪ.iː/) is a stony (S-type) asteroid in the outer asteroid belt's background population, approximately 84 kilometer in diameter. It was discovered by French astronomer Hermann Goldschmidt on 9 September 1860, from his balcony in Paris, France. Goldschmidt was ill when asked to name the asteroid, and requested his fellow asteroid-hunter Robert Luther to name it instead. Luther chose to name it after Danaë, the mother of Perseus in Greek mythology. Danaë was the first asteroid to have a diacritical character in its official name.
The asteroid is orbiting the Sun with a period of 5.15 years and is rotating on its axis once every 11.45 hours. In 1985, a study of lightcurve data suggested that Danaë may have a moon. If so, the main body would be an ellipsoid measuring 85 km × 80 km × 75 km (53 mi × 50 mi × 47 mi), and the moon would orbit 101 kilometres (63 mi) away, measuring 55 km × 30 km × 30 km (34 mi × 19 mi × 19 mi). The density of both would be 1.1 g/cm.
Excerpted from Wikipedia’s “61 Danaë” article, available under the CC BY-SA 4.0 licence.