volume (7) pt 2

February 18th, 2022

Hello Earthlings.

Welcome to 2022!!!

We are back at last for the second installment of a stroll through our solar system.

But first (!) Happy one year Mars-iversary Perseverance and Ingenuity!!! The two landed on the red planet on this day last year.

In honor of the martians, I give you this brilliant shadow selfie collage taken by Percy on February 16th, 2022 (sol 353).

Ok, are you ready?

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let’s go 

volume (7.2):

Our home stellar system: part 2(!)

Last time we visited the Sun and the terrestrial planets - Mercury, Venus, Earth and Mars. Now we move out further into our planetary neighborhood, and farther away from our sun to visit…

The Asteroid Belt (some notable objects) [in the space between Mars and Jupiter]:

Did you know the asteroid belt was there? Have you heard the story of how baby Jupiter and baby Saturn danced their way back toward the toddler sun and in the process Jupiter captured a bunch of tiny minions known as asteroids (and comets) in the space between Mars and Jupiter (and in orbit with Jupiter!)? The asteroid belt is one of the places astronomers believe, much like our own moon, hold relics and time capsules from an earlier era of the solar system.

Ceres as imaged by Dawn in 2015 (Image Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA)

• Ceres

  • classified scholarly as a dwarf planet, the largest celestial body in the belt (939.4 km//583.72 mi diameter)

  • the first “asteroid” to be discovered, only classified more recently (2006) as a dwarf planet - the only one in the inner solar system!

The asteroid Vesta as imaged by Dawn in 2011 (Image credit: NASA/JPL-Caltech/UCAL/MPS/DLR/IDA)

• Vesta

  • the largest asteroid in the belt (525.4 km//326.46 mi diameter)

  • the fourth asteroid discovered in the belt, sometimes referred to as 4 Vesta.

  • it is also the brightest asteroid in the belt

The Asteroid Ida and its moon Dactyl as imaged by Galileo in 1993 (Image Credit: NASA/JPL)

• Ida

  • the 243rd asteroid to be discovered since the first (Ceres!) was discovered in the 19th century by Giuseppe Piazzi

  • the only asteroid yet discovered to have its own moon!

  • (56 km//35mi long)

• Robot Visitors:

  Galileo was the first to fly past an asteroid, Gaspra, and the first to discover a moon of an asteroid, tiny Dactyl orbiting Ida.

  Upcoming missions to the asteroid belt include:

  • NEA Scout (expected to launch sometime 2022 catching a ride on Artemis 1, the first flight of the next phase of NASA’s attempts to revisit the Moon; a flyby CubeSat mission to Near Earth Asteroid 2020GE)

  • Psyche (scheduled to launch August 2022; a mission to study asteroid Psyche which has been observed to be made mostly of metal)

  • Hera (expected to launch 2024; visiting asteroids Didymos and Dimorphos)

Read the full series [our solar system]: the Asteroid Belt - coming soon right HERE

Jupiter ♃ [5th planet from the sun]:

Jupiter (and one of its largest moons - Europa off to the left) as imaged by Hubble August 25th, 2020 (Image Credits: NASA, ESA, STScI, A. Simon (Goddard Space Flight Center), M.H. Wong (University of California, Berkeley), and the OPAL team)

• gas giant planet (made mostly of gas, with a core)

• orbit averages 483.8 million miles from the sun (43.2 light-minutes)

• 1 day on Jupiter lasts just 10 Earth hours, 1 year on Jupiter lasts 12 Earth years.

• 79x (known) moons

• Robot visitors:

  You might have heard of lil ol’ Juno; a spacecraft that has been in orbit around Jupiter since 2016 taking incredible images illuminating close up features of Jupiter (and its moons, man!) on the daily. Juno is one of my personal favorite astrophotographing-robots. Long before Juno, in 1973 Jupiter was visited by Pioneer 10; the first ever satellite to travel past the asteroid belt into the outer solar system. But Pioneer 10 didn’t stay long, neither did Pioneer 11 (1974). Of course our most famous outer solar system adventurers are the Voyagers (1 & 2); launched in 1977 the twin probes were the first to visit the truest outer reaches of our solar system and brought us earthlings an entirely new point of view from the cosmos. Galileo (1995) would be the first to orbit Jupiter. Upcoming missions to Jupiter include:

  • Europa Clipper (expected to launch 2024; to study the habitability of Jupiter’s icy moon Europa)

  • JUICE: JUpiter ICy moons Explorer (expected to launch 2023; to study Jupiter and three of its largest moons; Ganymede, Callisto and Europa. JUICE will ultimately end up inserting itself into orbit around Ganymede, cool!)

Read the full series [our solar system]: Jupiter - coming soon right HERE

Saturn ♄ [6th planet from the sun]:

Saturn and four of its moons (Tethys, Dione, Rhea, and Mimas) as imaged by Voyager 2 on August 4th, 1981 (Image Credit: NASA/JPL)

• gas giant planet (made mostly of gas, with a core)

• orbit averages 890.8 million miles from the sun (79.3 light-minutes)

• 1 day on Saturn lasts just 11 Earth hours, 1 year on Saturn lasts 29 Earth years.

• 82x (known) moons

• Robot visitors:

  Only four missions have ever made it to Saturn: in 1979 NASA’s Pioneer 11 was the first to ever flyby the planet, both Voyagers (1&2) would flyby the gas giant as well in 1980 and 1981 respectively, and finally the first robot to orbit the planet (and brought a friend with it to drop off at Titan - Saturn’s largest moon!) was Cassini-Huygens, a joint mission by NASA, ESA and ASI. The only robot to ever orbit the planet, launched in 1997, entered its orbit around Saturn in 2004, dropped off the Huygens probe to Titan in 2005(the first and still only to date robot to land on another planet’s moon!), had its mission extended twice and would ultimately remain studying Saturn for a total of 294 complete orbits until its infamous dramatically scientifically enthralling death by decent into Saturn itself in 2017.

  • Dragonfly (expected to launch no sooner than 2027; a flying robot to land on Titan and further study its environment and organics)

Read the full series [our solar system]: Saturn - coming soon right HERE

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Did you know that Ceres was actually discovered and considered a proper planet in its time before even Neptune was even a thing?!

When Kepler was analyzing Tyco Brahe’s data in the late 1590’s he thought that there was too large a gap between the orbits of Mars and Jupiter to fit his then current model of where planetary orbits should lie.

Some 150 plus years later Johann Daniel Titus a German astronomer, while translating Charles Bonnet’s Contemplation de la Nature, notes that like Bonnet’s leaves on a plant there is an apparent pattern in the layout of the planets too (known now as the Titus-Bode Law). His model produced very close approximations for the radii of the orbits of the known planets of the time (Mercury, Venus, Earth, Mars, Jupiter, and Saturn) in astronomical units, and predicted the orbit of a so-called “missing planet” in the space between the orbits of Mars and Jupiter.

When William Herschel discovered Uranus in 1781, the planet’s orbit matched the Titus-Bode law almost perfectly, leading astronomers to conclude there really must be a planet between Mars and Jupiter.

In 1801, Giuseppe Piazzi observed a tiny moving object in an orbit with exactly the “missing planet” radius predicted by the Titus-Bode Law. He named it “Ceres” after the roman goddess of the harvest and patron of Sicily. Piazzi had initially believed it to be a comet but its lack of tail suggested it was a planet.

Thus the known planets became Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn and Uranus. Crazy!

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“Where there is matter, there is geometry” - Johannes Kepler

This has been space matter(s). 

See you in the starstuff.

-RRR

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