A very beautiful photo of Earth and Moon as seen through Saturn’s rings – an image taken by NASA’s Cassini spacecraft on April 13, 2017.

The image is created by “software engineer, planetary and climate data wrangler, science data visualization artist” Kevin M. Gill. He processed this image using calibrated red, green, and blue filtered images of Earth, its Moon, and Saturn’s rings taken by the Cassini orbiter on April 13, 2017. Earth and the F Ring have been brightened relative to the main rings. Close to, but not exactly, true color, according to Gill.

Earth and Moon as seen through Saturn’s rings

Earth and Moon as seen through Saturn's rings (2017 Cassini Image)
Earth and Moon as seen through Saturn’s rings (2017 Cassini Image). Original image: Kevin M. Gill on Flickr. CC BY NASA/JPL-Caltech/SSI/CICLOPS/Kevin M. Gill

A user on Reddit asked:

“Correct me if I am wrong, but the scale seems out – Earth and moon are too far apart. Could you even differentiate the two from as far away as Saturn? Yes, zoomed in, but still. If the distance between them is 384,400 km and Earth to Saturn is 1.2 billion km at its closest, is this still legit and not Earth + background star? Happy to be corrected and learn something new.”

But there’s nothing wrong with this image. The distance between the Moon and Earth is way greater than most people think. You could fit all the planets in the Solar System in that distance (see the image below).

The distance between the Earth and the Moon
All the planets of the Solar System could fit in the distance between the Earth and the Moon, which is around 384,400 km (238,855 miles). Image: The Science Asylum on Youtube

As another Reddit user pointed out, the Earth and Moon look certainly closer together than it should be in terms of maximum distance (see the image below – Earth and Moon as seen by the OSIRIS-REx spacecraft). But the issue here is simply the perspective angle the camera has and the geometry of the Earth and the Moon. The Moon is a bit closer or further to the camera than the Earth is.

Earth and Moon as seen by OSIRIS-REx. October 2, 2017.
Earth and Moon as seen by OSIRIS-REx. This composite image of the Earth and Moon above is made from data captured by NASA’s OSIRIS-REx’s MapCam instrument on October 2, 2017. The purpose of OSIRIS-REx spacecraft (an acronym for Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) is to study, map and return samples for detailed analysis from asteroid 101955 Bennu, a carbon-rich hunk of rock that might contain organic materials or molecular precursors to life. It was launched on September 8, 2016, and the expected return date is September 24, 2023. OSIRIS-REx is the first NASA spacecraft to return samples from an asteroid. 101955 Bennu has a cumulative 1-in-2,700 chance of impacting Earth between 2175 and 2199.

Cassini-Huygens space-research mission

The Cassini-Huygens space research mission, commonly called Cassini, involved a collaboration between the United States National Aeronautics and Space Administration (NASA), the European Space Agency (ESA), and the Italian Space Agency (ASI) to send a probe to study the planet Saturn and its system, including its rings and natural satellites. The Flagship-class robotic spacecraft comprised both NASA’s Cassini probe and ESA’s Huygens lander, which landed on Saturn’s largest moon, Titan.

Cassini spacecraft launched on October 15, 1997.

The ASI/NASA Cassini orbiter, named for the Italian astronomer Giovanni Domenico Cassini (8 June 1625 – 14 September 1712), discoverer of Saturn’s ring divisions and four of its satellites; and the ESA-developed Huygens probe was named after Christiaan Huygens (14 April 1629 – 8 July 1695), a Dutch astronomer who in 1655 discovered Titan, Saturn’s largest moon.

Cassini had several objectives, including:

  • Determining the three-dimensional structure and dynamic behavior of the rings of Saturn.
  • Determining the composition of the satellite surfaces and the geological history of each object.
  • Determining the nature and origin of the dark material on Iapetus’s leading hemisphere.
  • Measuring the three-dimensional structure and dynamic behavior of the magnetosphere.
  • Studying the dynamic behavior of Saturn’s atmosphere at cloud level.
  • Studying the time variability of Titan’s clouds and hazes.
  • Characterizing Titan’s surface on a regional scale.

The primary mission for Cassini was completed on July 30, 2008. Its mission was extended twice.

The spacecraft made its final approach to Saturn and dove into the planet’s atmosphere on Friday, September 15, 2017. Loss of contact with the Cassini spacecraft took place on September 15 at 7:55:46 a.m. EDT (4:55:46 a.m. PDT). This method was chosen to prevent biological contamination of any of the moons of Saturn now thought to offer potentially habitable environments.

This is an artist’s concept of Cassini during the Saturn Orbit Insertion (SOI) maneuver, just after the main engine has begun firing. The spacecraft is moving out of the plane of the page and to the right (firing to reduce its spacecraft velocity with respect to Saturn) and has just crossed the ring plane. The SOI maneuver, approximately 90 minutes long, allowed Cassini to be captured by Saturn’s gravity into a five-month orbit. Cassini’s close proximity to the planet after the maneuver offers a unique opportunity to observe Saturn and its rings at extremely high resolution. This image was cataloged by the Jet Propulsion Laboratory of the United States National Aeronautics and Space Administration (NASA) under Photo ID: PIA03883.


M. Özgür Nevres

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