Pioneer 10 launched to Jupiter

Pioneer 10 launched to Jupiter

Pioneer 10, the world’s first outer-planetary probe, is launched from Cape Canaveral, Florida, on a mission to Jupiter, the solar system’s largest planet. In December 1973, after successfully negotiating the asteroid belt and a distance of 620 million miles, Pioneer 10 reached Jupiter and sent back to Earth the first close-up images of the spectacular gas giant. In June 1983, the NASA spacecraft left the solar system and the next day radioed back the first scientific data on interstellar space. NASA officially ended the Pioneer 10 project on March 31, 1997, with the spacecraft having traveled a distance of some six billion miles.

Headed in the direction of the Taurus constellation, Pioneer 10 will pass within three light years of another star—Ross 246—in the year 34,600 A.D. Bolted to the probe’s exterior wall is a gold-anodized plaque, 6 by 9 inches in area, that displays a drawing of a human man and woman, a star map marked with the location of the sun, and another map showing the flight path of Pioneer 10. The plaque, intended for intelligent life forms elsewhere in the galaxy, was designed by astronomer Carl Sagan.

Pioneer 10: Greetings from Earth

Pioneer 10 was a breakthrough mission, accomplishing several firsts among spacecraft. It was the first to fly beyond Mars, the first to fly through the asteroid belt, first to swing by the planet Jupiter, and first to leave the solar system. Along the way, the spacecraft even generated a mystery of its own – the Pioneer Anomaly – that took decades for scientists to solve.

Thanks to Pioneer 10's pictures, the planet Jupiter and its moons, which were formerly only small circles in a telescope, became large, vibrant worlds in the eyes of scientists. For decades after those images beamed back to Earth, Pioneer 10 kept going. It sent valuable scientific data about the sun and cosmic rays before its signal became too faint for Earthlings to hear.

Pioneer 10 also carries a plaque with a message to any intelligent life it might encounter on its journey. The Pioneer plaque includes diagrams of Earth's location and drawings of a man and a woman.

Instruments and art

Launched on March 2, 1972, Pioneer 10 was the latest in a series of missions to explore space, which was still a very new frontier at the time. The earliest Pioneers aimed for the moon, while later generations forged farther and farther into space.

This spacecraft, powered by four radioisotope thermoelectric generators, measured 9.5 feet (2.9 meters) long and weighed 570 pounds (258 kilograms). Among the instruments and camera equipment on board, Pioneer also carried something special: a six- by nine-inch (15.2 by 22.8 centimeters) gold plaque.

The plaque depicts two nude figures – a man and a woman – along with diagrams of the solar system and the sun's position in space. It was intended to serve as a map to Earth for any extraterrestrials who might be curious about who made the spacecraft.

Two people designed the plaque: famed television host and astronomer Carl Sagan, and Frank Drake, founder of SETI and author of an equation that measures the likelihood of communicating with intelligent life.

Imaging Jupiter

Pioneer 10's primary target was the planet Jupiter. It launched from Earth on an Atlas-Centaur three-stage launcher, intended to boost the spacecraft to 32,400 mph (52,142 kph). Sailing away from Earth faster than any spacecraft before it, Pioneer soared by the moon just 11 hours later and made it past Mars in only three months.

Perhaps Pioneer's most dangerous phase was the asteroid belt between Mars and Jupiter, which it reached on July 15. Pioneer faced the risk of colliding with bits of asteroids, anywhere from the size of a small particle to rocks as big as the state of Alaska, according to NASA. But it made it safely to the other side and reached Jupiter on Dec. 3, 1973.

Pioneer 10 was just intended to be a scout for future missions, so its stay at Jupiter was brief. It came within 81,000 miles (130,000 kilometers) of the surface as it sailed past. Pictures beamed back to Earth revealed Jupiter as a liquid giant, while other instruments recorded information on Jupiter's radiation belts and magnetic fields.

The spacecraft also sent back snapshots of some of Jupiter's moons. Although the shots were taken from a distance, scientists could pick out shadows and featureson Europa, Ganymede, Io and Callisto. It was incredible resolution compared to the almost 400 years of observations previously done through telescopes.

On through the outer solar system

Pioneer's story does not end there. For about a quarter-century, the little spacecraft flew farther and farther away from Earth and continued producing science. It measured particles streaming from the sun, and cosmic rays incoming from outside the solar system.

Along with sister ship Pioneer 11, the spacecraft also embroiled scientists in an intergalactic mystery. For decades, NASA was puzzled as to why the two probes travelled 3,000 miles (4,828 km) less than projected, every single year.

Dubbed the "Pioneer Anomaly," it was only in 2012 that NASA found out what happened: heat flowing through the spacecrafts' power systems and instruments was pushing back on the Pioneers as they moved out of the solar system.

NASA concluded Pioneer's science mission on March 31, 1997, but kept track of the spacecraft through the Deep Space Network. Obtaining its signal was used as training for flight controllers looking to get data from the Lunar Prospector mission, which flew for 19 months before being deliberately crashed into the moon's surface in 1999.

Pioneer 10 last sent data back to Earth on April 27, 2002. Its decaying signals were just too faint for NASA's antennas to pick up anymore.

As far as we know, the spacecraft sails on. NASA warmly refers to Pioneer 10 as a "ghost ship" of the outer solar system as the spacecraft coasts in the general direction of Aldebaran – the eye of the bull in the constellation Taurus.

Residents of that region of space will need to be patient if they want to see Pioneer 10. NASA expects it will take the spacecraft 2 million years to traverse the 68 light-years of space to Aldebaran.

Pioneer 10

One of the things Pioneer 10 studied was the intense radiation that surrounds Jupiter. The massive planet has "the harshest radiation environment in the solar system," according to NASA. A strong magnetic field draws the radiation into a ring the shape of a doughnut around Jupiter, which poses a problem for visiting probes: Pioneer 10 fulfilled all of its Jupiter mission objectives except one, which failed because the radiation "triggered false commands" in the probe's electronics, according to NASA. In order to avoid the radiation, Juno will make more than 30 orbits that take it into the narrow space between Jupiter and the radiation doughnut. Launched in March 1972, Pioneer 10 lived up to its name by becoming the first space probe to ever cruise past the Jovian system. The spacecraft came to within 81,000 miles (130,365 kilometers) of the tops of the clouds that cover Jupiter.

Before its pass by Jupiter, Pioneer 10 studied the asteroid belt, and after the flyby it continued on a journey to exit the solar system. Its last message to Earth was received on Jan. 23, 2003. It carries a golden plaque that includes a map of Earth's location.


  • Pioneer 10 – launched in 1972, flew past Jupiter in 1973 and is heading in the direction of Aldebaran (65 light years away) in the constellation of Taurus. Contact was lost in January 2003, and it is estimated to have passed 120 astronomical units (AU one AU is roughly the average distance between Earth and the Sun: 150 million kilometers (93 million miles)). [1]
  • Pioneer 11 – launched in 1973, flew past Jupiter in 1974 and Saturn in 1979. Contact was lost in November 1995, and it is estimated to be at around 100 AU. [2] The spacecraft is headed toward the constellation of Aquila, northwest of the constellation of Sagittarius. Barring an incident, Pioneer 11 will pass near one of the stars in the constellation in about 4 million years. [3]
  • Voyager 2 – launched in August 1977, flew past Jupiter in 1979, Saturn in 1981, Uranus in 1986, and Neptune in 1989. The probe left the heliosphere for interstellar space at 119 AU on 5 November 2018. [4]Voyager 2 is still active. It is not headed toward any particular star, although in roughly 40,000 years it should pass 1.7 light-years from the star Ross 248. [5] If undisturbed for 296,000 years, it should pass by the star Sirius at a distance of 4.3 light-years.
  • Voyager 1 – launched in September 1977, flew past Jupiter in 1979 and Saturn in 1980, making a special close approach to Saturn's moon Titan. The probe passed the heliopause at 121 AU on 25 August 2012 to enter interstellar space. [6]Voyager 1 is still active. It is headed towards an encounter with star AC +79 3888, which lies 17.6 light-years from Earth, in about 40,000 years. [7]
  • New Horizons – launched in 2006, the probe flew past Jupiter in 2007 and Pluto on 14 July 2015. It flew past the Kuiper belt object 486958 Arrokoth on January 1, 2019, as part of the Kuiper Belt Extended Mission (KEM). [8]

Although other probes were launched first, Voyager 1 has achieved a higher speed and overtaken all others. Voyager 1 overtook Voyager 2 a few months after launch, on 19 December 1977. [9] It overtook Pioneer 11 in 1983, [10] and then Pioneer 10—becoming the probe farthest from Earth—on February 17, 1998. [11]

Depending on how the "Pioneer anomaly" affects it, New Horizons will also probably pass the Pioneer probes, but will need many years to do so. It will not overtake Pioneer 11 until the 22nd century, will not overtake Pioneer 10 until the end of that century, and will never overtake the Voyagers. [10]

Name Launched Distance (AU)
(as of Apr 2021)
Speed (km/s)
Voyager 1 1977 152.0 17.0
Pioneer 10 1972 128.3 11.9
Voyager 2 1977 126.7 15.4
Pioneer 11 1973 105.1 11.9
New Horizons 2006 50.0 [12] 13.9

For comparison, Pluto's average distance (semi-major axis) is about 40 AU.

Solar escape velocity is a function of distance (r) from the Sun's center, given by

where the product G Msun is the heliocentric gravitational parameter. The initial speed required to escape the Sun from its surface is 618 km/s (1,380,000 mph), [15] and drops down to 42.1 km/s (94,000 mph) at Earth's distance from the Sun (1 AU), and 4.21 km/s (9,400 mph) at a distance of 100 AU. [16] [17]

Voyager 1 and 2 speed and distance from the Sun

Pioneer 10 and 11 speed and distance from the Sun

New Horizons speed and distance from the Sun.

Every planetary probe was placed into its escape trajectory by a multistage rocket, the last stage of which ends up on nearly the same trajectory as the probe it launched. Because these stages cannot be actively guided, their trajectories are now different from the probes they launched (the probes were guided with small thrusters that allow course changes). However, in cases where the spacecraft acquired escape velocity because of a gravity assist, the stages may not have a similar course and there is the remote possibility that they collided with something. Some objects in heliocentric orbit have been reidentified with a telescope, and so their trajectories can be confirmed. The stages on an escape trajectory are:

  • Pioneer 10 third stage, a TE364-4 variant of the Star-37 solid fuel rocket. [18]
  • Voyager 1 fourth stage, a Star 37E solid fuel rocket. [19]
  • Voyager 2 fourth stage, a Star 37E solid fuel rocket. [19]
  • New Horizons third stage, a Star 48B solid fuel rocket, is on a similar escape trajectory out of the Solar System as New Horizons, even arriving at Jupiter 6 hours before New Horizons. On October 15, 2015 it passed through Pluto's orbit at a distance of 213 million kilometers (over 1 AU) distant from Pluto. [20][21] This was four months after the New Horizons probe did. [22]

In addition, two small yo-yo de-spin weights on wires were used to reduce the spin of the New Horizons probe prior to its release from the third-stage rocket. Once the spin rate was lowered, these masses and the wires were released, and so are also on an escape trajectory out of the Solar System. [23] [24] None of these objects are trackable (they have no power or radio antennae, spin uncontrollably, and are too small to be detected), and their exact positions are unknowable beyond their projected Solar System escape trajectories.

The third stage of Pioneer 11 is thought to be in solar orbit because its encounter with Jupiter would not have resulted in escape from the Solar System. [19] [ better source needed ] Pioneer 11 gained the required velocity to escape the Solar System in its subsequent encounter with Saturn. [ dubious – discuss ]

The only objects to date to be launched directly into a solar escape trajectory were the New Horizons spacecraft, its third stage, and the two de-spin masses. The New Horizons Centaur (second) stage is not escaping it is in a 2.83-year heliocentric (solar) orbit. [20]

The Pioneer 10 and 11, and Voyager 1 and 2 Centaur (second) stages are also in heliocentric orbits. [24] [25]

In order to leave the Solar System, the probe needs to reach the local escape velocity. After leaving Earth, the Sun's escape velocity is 42.1 km/s. In order to reach this speed, it is highly advantageous to use the orbital speed of the Earth around the Sun, which is 29.78 km/s. By passing near a planet, a probe can gain extra speed with a gravity assist.

On January 19, 2006 the New Horizons spacecraft to Pluto was launched directly into a solar-escape trajectory at 16.26 kilometers per second (58,536 km/h 36,373 mph) from Cape Canaveral using an Atlas V version with 5 of the AJ-60A SRBs and the Common Core Booster, Centaur upper stage, and Star 48B third stage. [26] New Horizons passed the Moon's orbit in just nine hours. [27] [28]

Propulsive units for New Horizons, which was launched directly to a solar escape velocity from Earth: [26]

Solving Space: Pioneer 10 Launch

Launched on March 2, 1972, Pioneer 10 was the first spacecraft to travel through the asteroid belt, and the first spacecraft to make direct observations and obtain close-up images of Jupiter. The mission was a spectacular success through its completion on January 23, 2003. Solve Space by unscrambling this image and learn more about Pioneer 10 and how we get there!

Learn More About It

  • Originally designed for a 21-month mission to fly by Jupiter, Pioneer 10 lasted more than 30 years.
  • Pioneer 10 sent its last signal to Earth in January 2003 from a distance of 7.6 billion miles (12.23 billion kilometers).
  • Its accomplishments are unmatched by any other robotic spacecraft to date.
  • The spacecraft’s mass was 569 pounds (258 kilograms).

All of Its Firsts

This spacecraft provided crucial information about our solar system and neighboring planets which will help with our journey into deep space. It notched a series of firsts unmatched by any other robotic spacecraft:

  • First spacecraft placed on a trajectory to escape the solar system into interstellar space
  • First spacecraft to fly beyond Mars
  • First spacecraft to fly through the main asteroid belt
  • First spacecraft to fly past Jupiter
  • Crossed the orbit of Neptune to become the first human-made object to go beyond Neptune
  • First spacecraft to use all-nuclear electrical power

Experience More

  • Walk through exhibits while learning more about space exploration in our exhibits and experiences.
  • For more firsts and pioneers, watch our past Thought Leader Series highlighting NASA recruiting its first six women astronauts and hear retired astronauts Dr. Shannon Lucid, Dr. Rhea Seddon and Dr. Anna Fisher discuss their amazing experiences during this Women’s History Month 2021.

Plan your stay

A good night's sleep is crucial for a full day of space exploration. Find and compare great local hotels with our search tool.

As planning for the Pioneer 10 and 11 missions progressed, mission scientists found themselves desiring a third probe. In 1971, a formal mission study was proposed for a spacecraft to be launched to Jupiter in 1974, where it would use the gas giant as a gravitational slingshot to travel outside the ecliptic. This was the first Out-Of-The-Ecliptic mission (OOE) proposed, for Jupiter and solar (Sun) observations. [1]

NASA/Ames Research Center would have managed the project. The NASA contractor TRW Systems Group (formerly Space Technology Laboratories) would have constructed Pioneer H from the flight-qualified spare components intended for the Pioneer F and G probes (designated Pioneer 10 and Pioneer 11 after launch).

NASA management did not approve the mission proposal, and it was never launched in 1974. In 1976 NASA transferred the craft (without RTG) to the Smithsonian Institution. In January 1977, Pioneer H was moved to the National Air and Space Museum, where it was eventually displayed as a replica of Pioneer 10.

The Pioneer H mission concept was finally realized with the Ulysses mission, which achieved the OOE orbit originally envisioned for Pioneer H. The Juno mission, currently at Jupiter in a polar orbit, is taking the magnetometer observations of Jupiter's poles that Pioneer H would have performed.

Pioneer H hangs in the Milestones of Flight Gallery at the National Air and Space Museum in Washington, D.C., serving as a stand-in for the Pioneer 10 probe. [2]

While described in official Smithsonian records as a "replica", the spacecraft was considered fully functional by Pioneer mission planners (though its RTGs were never installed). Mark Wolverton quotes James Van Allen in The Depths of Space: [3]

We mounted an intensive campaign to launch the flight-worthy spare spacecraft and its instrument complement on a low-cost, out-of-ecliptic mission via a high-inclination flyby of Jupiter. However, our case fell on deaf ears at NASA headquarters, and the spare spacecraft now hangs in the main gallery of the National Air and Space Museum, at 1 AU and zero ecliptic latitude.

Pioneer 10 & 11

Pioneer 10 was the first spacecraft intended to fly by Jupiter, surviving the intense radiation that surrounds the giant planet and then on a trajectory that would take it out of the Solar System.


The spacecraft became the first to fly beyond Mars' orbit, through the asteroid belt, and close to Jupiter, blazing a trail for the two Voyager spacecraft that were to follow and conduct more in-depth surveys. During the passage by Jupiter, Pioneer 10 obtained the first close-up images of the planet, charted Jupiter's intense radiation belts, located the planet's magnetic field, and discovered that Jupiter is predominantly a liquid planet. Long before and after flying by Jupiter, Pioneer 10 transmitted data on the magnetic fields, energetic particle radiation and dust populations in interplanetary space.

Pioneer 11 was the first mission to explore Saturn and the second spacecraft in humanity's early reconnaissance of the outer solar system.

Pioneer 11

  • Launched on April 5, 1973
  • Flew past Jupiter and Saturn
  • First spacecraft to fly past Saturn
  • RTGs operated for over 22 years, until communications link lost

Powered by:

Four SNAP-19 RTGs, with heat from twelve RHUs


Pioneer 11 was the first mission to explore Saturn and the second spacecraft in humanity's early reconnaissance of the outer solar system. The spacecraft carried instruments to study magnetic fields, the solar wind and the atmospheres, moons and other aspects of Jupiter and Saturn.


During its flyby of Jupiter Pioneer 11 obtained dramatic images of the Great Red Spot, made the first observation of the immense polar regions, and determined the mass of Jupiter's moon, Callisto.

At Saturn, Pioneer 11 took the first close-up pictures of the planet. Its instruments located two previously undiscovered small moons and an additional ring, charted Saturn's magnetosphere and magnetic field and found its planet-size moon, Titan, to be too cold for life. Hurtling underneath the ring plane, Pioneer 11 sent back amazing pictures of Saturn's rings. The rings, which normally seem bright when observed from Earth, appeared dark in the Pioneer pictures, and the dark gaps in the rings seen from Earth appeared as bright rings. It also found that the planet it emits more than twice as much heat as it receives from the Sun. Photographs revealed a more featureless atmosphere than that of Jupiter, and calculations based on data from Pioneer 11 suggested that Saturn is primarily liquid hydrogen with a core of about 10 Earth masses.

The dormant spacecraft is now headed out of our solar system in the general direction of Sagittarius, toward the center of the galaxy. Both Pioneers 10 and 11 carry a plaque with a message for any intelligent beings that might find them.

The Pioneer Anomaly

Beginning in the early 1980s NASA navigators noticed an unexpected slowing of the two Pioneers in their outward trek from the solar system. Recent analysis has shown that the slowing is due to a subtle effect of heat being given off by their radioisotope generators. Read more

40 Years Ago: NASA's Pioneer 10 Snaps 1st Up-Close Look at Jupiter (Photo)

On Dec. 4, 1973, exactly 40 years ago this week, NASA's Pioneer 10 probe beamed the first up-close images of Jupiter back home.

After traveling away from Earth for more than a year and navigating a risky route through the asteroid belt, Pioneer 10 became the first spacecraft to reach Jupiter, sailing within 81,000 miles (130,000 kilometers) of the planet's cloud tops.

The Jupiter images in this photo montage, released by NASA in honor of Pioneer 10's flyby anniversary, show Jupiter growing in size into to a warped crescent shape before shrinking as spacecraft flew away. [Target: Jupiter - 9 Missions to the King of Planets]

Pioneer 10, which launched on March 2, 1972, also captured images of Jupiter's moons, such as Europa and Ganymede, and it measured the planet's magnetosphere, radiation belts, atmosphere and interior.

The mission paved the way for more ambitious explorations of the solar system, and several more spacecraft visited Jupiter in the decades that followed, including Voyager 1 and 2, the Galileo spacecraft, the Saturn-bound Cassini-Huygens and New Horizons probe en route to Pluto. Those probes sent back even more amazing color portraits of the gas giant, its swirling storms and its polar auroras. In 2011, NASA launched its $1.1 billion Juno mission to study Jupiter. It should arrive at the planet in 2016.

Pioneer 10 sent it last signal back to Earth in January 2003 from billions of miles away. It is expected to eventually join Voyager 1 as one of the few manmade objects to leave our solar system. In case Pioneer 10 ever ends up in the hands of extraterrestrials, the spacecraft and its sister vehicle Pioneer 11 both carry gold plaques to describe where they came from, with images of a man and woman as well as a diagram of our solar system. The plaques, which were co-designed by SETI founder Frank Drake and television host and astronomer Carl Sagan, inspired the golden records aboard Voyager 1 and 2.


Credit for naming the first probe has been attributed to Stephen A. Saliga, who had been assigned to the Air Force Orientation Group, Wright-Patterson AFB, as chief designer of Air Force exhibits. While he was at a briefing, the spacecraft was described to him, as, a "lunar-orbiting vehicle, with an infrared scanning device." Saliga thought the title too long, and lacked theme for an exhibit design. He suggested, "Pioneer", as the name of the probe, since "the Army had already launched and orbited the Explorer satellite, and their Public Information Office was identifying the Army, as, 'Pioneers in Space,'" and, by adopting the name, the Air Force would "make a 'quantum jump' as to who, really, [were] the 'Pioneers' in space.'" [1]

The earliest missions were attempts to achieve Earth's escape velocity, simply to show it was feasible and to study the Moon. This included the first launch by NASA which was formed from the old NACA. These missions were carried out by the Air Force Ballistic Missile Division, Army, and NASA. [2]

Able space probes (1958–1960) Edit

    (Thor-Able 1, Pioneer) – Lunar orbiter, destroyed (Thor failure 77 seconds after launch) August 17, 1958 (Thor-Able 2, Pioneer I) – Lunar orbiter, missed Moon (third stage partial failure) October 11, 1958 (Thor-Able 3, Pioneer II) – Lunar orbiter, reentry (third stage failure) November 8, 1958 (Atlas-Able 4A, Pioneer W), Launch vehicle lost September 24, 1959 (Atlas-Able 4, Atlas-Able 4B, Pioneer X) – Lunar probe, lost in launcher failure November 26, 1959 (Pioneer P-2, Thor-Able 4, Pioneer V) – interplanetary space between Earth and Venus, launched March 11, 1960 [3] (Atlas-Able 5A, Pioneer Y) – Lunar probe, failed to achieve lunar orbit September 25, 1960 (Atlas-Able 5B, Pioneer Z) – Lunar probe, lost in upper stage failure December 15, 1960

Juno II lunar probes (1958–1959) Edit

    – Lunar flyby, missed Moon due to launcher failure December 6, 1958 – Lunar flyby, achieved Earth escape velocity, launched March 3, 1959

Five years after the early Able space probe missions ended, NASA Ames Research Center used the Pioneer name for a new series of missions, initially aimed at the inner Solar System, before the flyby missions to Jupiter and Saturn. While successful, the missions returned much poorer images than the Voyager program probes would five years later. In 1978, the end of the program saw a return to the inner Solar System, with the Pioneer Venus Orbiter and Multiprobe, this time using orbital insertion rather than flyby missions.

The new missions were numbered beginning with Pioneer 6 (alternate names in parentheses).

Interplanetary weather Edit

The spacecraft in Pioneer missions 6, 7, 8, and 9 comprised a new interplanetary space weather network:

  • Pioneer 6 (Pioneer A) – launched December 1965
  • Pioneer 7 (Pioneer B) – launched August 1966
  • Pioneer 8 (Pioneer C) – launched December 1967
  • Pioneer 9 (Pioneer D) – launched November 1968 (inactive since 1983)
  • Pioneer E – lost in launcher failure August 1969

Pioneer 6 and Pioneer 9 are in solar orbits with 0.8 AU distance to the Sun. Their orbital periods are therefore slightly shorter than Earth's. Pioneer 7 and Pioneer 8 are in solar orbits with 1.1 AU distance to the Sun. Their orbital periods are therefore slightly longer than Earth's. Since the probes' orbital periods differ from that of the Earth, from time to time, they face a side of the Sun that cannot be seen from Earth. The probes can sense parts of the Sun several days before the Sun's rotation reveals it to ground-based Earth orbiting observatories.

10 Facts About Jupiter

1. Jupiter is the Fastest Spinning Planet

Jupiter spins at a speed of 28,273 miles per hour, which is almost 28 times the speed of Earth. It takes, on average, 10 hours for Jupiter to make a full rotation, meaning that Jupiter also has the shortest days of all the planets in our Solar System. Unlike Earth, it is a gas planet, which means that it does not spin as a solid sphere. The equator of the gas giant spins a little faster than the rest of its mass, and this forces it to bulge out in this area.

2. The Gas Giant Has Rings

After a five-year disappearance, Charles Jevington explained how he had discovered that Jupiter has rings. It was a common belief that Saturn was the only planet with that particular feature in our solar system and there was no evidence to suggest otherwise. However, Jevington was met with disbelief and written off as a loon. Whether or not he discovered these rings on an extraterrestrial journey, is definitely up for debate, but several years later he was proven right. The rings were first encountered by Voyager 1 in 1979 and later investigated by spacecraft Galileo in 1990. Jupiter has four sets of rings:

  • The Thebe gossamer ring
  • The Amalthea gossamer ring
  • The main ring
  • The halo ring

The rings of Jupiter. Source: NASA, public domain.

These rings are difficult to see because they are dark and made up of small bits of dust. The spacecraft, Galileo, had a hand in discovering the source of the dust. Meteors hit the inner moon, which kicks it up and sends it into orbit around Jupiter.

3. Jupiter Can Be Seen Without a Telescope

Jupiter is the fourth brightest object in the sky. First is the Sun, then the Moon, and then Venus. It will appear as bright as, or brighter than, the stars. In order to see Jupiter, there are methods that depend on its place in the constellations, the time of day, and your location. A beautiful image to be seen is the northern lights on Jupiter.

4. It Has the Strongest Magnetic Field

An estimate of Jupiter’s magnetic field puts it at 20,000 times stronger than Earth’s. It is created in a different way than our planet’s as well. Earth has a magnetic field generated by a circulating core of molten iron and nickel, while Jupiter’s is said to come from hydrogen and helium. While there are no facts about Jupiter that suggest there is a rocky core within it, there may be. Truth be told, scientists are unsure of what actually causes its magnetic field. Due to this, there is an enormous magnetosphere. Jupiter’s magnetosphere is 150 times the size of Jupiter itself and 15 times larger than the sun. That makes it the largest structure in our solar system.

5. Jupiter’s Great Red Spot

Facts about Jupiter have been gathered to suggest that the big red spot is actually an anticyclonic storm. This storm is said to have been raging for over 180 years and possibly more than 350 years.

The Great Red Spot on Jupiter. February 1979. Photo credit: NASA.

6. There Have Been 9 Missions to the Gas Giant

Nine missions have taken place within the last five decades to gather facts about Jupiter. Each spacecraft had a specific mission, and most of them weren’t only visiting the gas giant. Here is a timeline of those spacecraft:

  • Pioneer 10 – In March of 1972, Pioneer 10 was launched to study Jupiter’s intense radiation. It was the first spacecraft to ever witness the Jovian system. It fulfilled all but one mission objective because the radiation triggered false alarms within itself.
  • Pioneer 11 – Launched in April of 1973, this spacecraft came three times closer than its sister, the Pioneer 10. Pioneer 11 captured fantastic photos of Jupiter’s Great Red Spot and gathered more information about its radiation belt.
  • Voyager 1 – This spacecraft left Earth in September of 1977 and came close enough to Jupiter to take more than 18,000 photos of the planet in March of 1979. Scientists are still receiving data from this probe.
  • Voyager 2 – Launched in August of 1977, Voyager 2 reached Jupiter in July of 1979. Observations by this probe revealed active volcanoes on one of Jupiter’s moons, Io, and still transmits information back to us today.
  • Galileo – First launched in October of 1989, it arrived 6 years later on Jupiter. It studied the magnetosphere and thunderstorms while in orbit and even dropped a probe into the atmosphere to measure temperature, wind, and pressure.
  • Ulysses – Launched in 1990, the Ulysses swung around Jupiter in 1992. It studied Jupiter’s atmosphere and magnetic field among other things.
  • Cassini-Huygens – This probe captured about 26,000 images of Jupiter’s system from December 2000 to around May 2001.
  • New Horizons – While traveling past Jupiter in February of 2007, New Horizons took fantastic photos of the planet’s raging storms.
  • Juno – Juno began its five-year journey to Jupiter in 2011. It entered into a polar orbit of Jupiter on July 5, 2016. NASA expects the probe to reveal facts about the planet’s composition, formation, and magnetic and gravity fields.

7. Named After a Roman God

Being the largest planet in our solar system, Jupiter was rightly named after the king of the gods in Roman Mythology. The Romans called this planet Jupiter because it was the largest object in the sky. They believed that made it the most powerful. Jupiter was not only the king of the gods but also the god of the sky and thunder, the direct translation of Zeus from the Greeks.

8. It Has the Largest Moon

Ganymede is the largest moon in our solar system, and it belongs to Jupiter. Interestingly enough, it is the only moon known to have a magnetic field.

9. There is No Season Change

Jupiter has a tilt of only three degrees, which means that this planet does not experience seasonal changes. Earth has a tilt of 23 degrees, and that is why we do experience the seasons. Most other planets also have a similar trait, which makes the gas giant even more unique.

10. 67 Moons Surround the Giant

The main moons of Jupiter are the Galilean moons. They are Io, Europa, Ganymede, and Callisto. Facts about Jupiter always point to its massive size and its moons follow the same rule. These four are some of the largest objects in the solar system. They are bigger than any known dwarf planet. Of the remaining moons, 14 of them have yet to be named.

The Galilean Satellites are Jupiter’s largest moons, Io being the closest. Public domain.

Space travel will continue to be a fascinating topic, and Jupiter adds to the mystique. Though we know a bit, this planet is still vastly mysterious. Many facts about Jupiter are still being discovered as we continue to ask questions about the unending abyss outside the boundaries of our planet.