Facts about Planet Jupiter

The largest planet in the solar system and the third brightest object when viewed from Earth, Jupiter is as easy to spot as the Moon and Venus in the night sky. Known for its Great Red Spot and distinct coloured stripes, this planet is a mass of swirling gas. Below we go through some interesting Jupiter facts and questions, including what it’s like on the planet, does Jupiter have any moons, what missions have we sent there, plus much more.

How far away is Jupiter?

Jupiter is the fifth planet in the solar system. Depending on its orbital position, Jupiter lies at a distance of between 741 million kilometers (closest) and 817 kilometers (farthest) from the Sun. Sunlight takes about 43 minutes to reach the planet.

Given the positions of Earth and Jupiter in their respective orbits, the closest distance between them is 588 million kilometers and the farthest is 968 million kilometers. Interestingly, Jupiter can be far brighter than Venus when closest to the Earth.

How big is Jupiter?

Jupiter is a large planet in terms of volume. It can hold about 1,321 Earths; however, it is just 318 times bigger than Earth in terms of mass. The planet is less dense than Earth as it hardly has any landmass.

With an equatorial diameter spanning 142,984 kilometers, it is 11 times wider than Earth. The planet’s polar diameter spans 133,709 kilometers.

What’s it like on Jupiter?

Jupiter is a windy planet, mainly because it rotates quite fast; faster than all other planets and, hence, has the shortest day lasting just 10 hours. Wind speeds range between 192 miles per hour (mph) to over 400 mph. Exceptionally high wind speeds have resulted in a giant spinning storm with a diameter 3.5 times of the Earth, which appears as a prominent red spot on the planet. We’re yet to find out what causes the red coloration. Interestingly, the signature red spot has been observed ever since the 17th century.

The temperature in the clouds average at −145°C and gets warmer towards the center. Jupiter’s core temperature is estimated to be around 24,000 °C, far hotter than the temperatures on the Sun’s surface.

Beneath Jupiter’s colorful clouds lies an ocean of liquid hydrogen. The high levels of pressure and temperatures cause hydrogen to condense, making it an electrical conductor, which in turn generates a powerful magnetic field 20 times stronger than Earth.

Jupiter does not have a solid surface as it is made of gases. It is, therefore, not possible for spacecraft to land on Jupiter. They can’t fly too close either as the strong gravitational and magnetic field of the planet, plus extreme temperatures, will crush, liquefy and vapourize any material that comes in contact with the atmosphere. The gravitational force on the planet is 2.4 times the force felt on Earth.

Jupiter storm
This color-enhanced image of a massive, raging storm in Jupiter’s northern hemisphere was captured by NASA’s Juno spacecraft during its ninth close flyby of the gas giant planet. Image credit: NASA/JPL-Caltech/SwRI/MSSS.

What is Jupiter made of?

Jupiter is a “gas giant”, this simply means the planet’s atmosphere is a swirly mass of gases, mainly hydrogen (90 percent) and helium. Traces of other gases such as ammonia, methane, hydrogen sulfide, phosphorine, neon, oxygen are also known to be present. The planet has no real surface. It may have a rocky core of iron and minerals like quartz. The core could also be a thick scorching melt of gases as the high atmospheric pressure and temperature under the surface are powerful enough to compress the gases into liquid form. We don’t have enough information as yet.

Is there life on Jupiter?

There is no evidence of life on Jupiter. According to our knowledge, the planet composition and climatic conditions are not favorable for living organisms to thrive.

Does Jupiter have rings?

Though not visible, Jupiter does have three rings made of dust particles that get created when meteoroids crash into the many moons surrounding Jupiter. These rings were only found in 1979 by the Voyager 1 spacecraft.

Jupiter south pole
Jupiter’s south pole captured by Juno. Image credit: NASA/JPL-Caltech/SwRI/MSSS/Gabriel Fiset.

How many moons does Jupiter have?

In 2018, 69 moons have been discovered in Jupiter’s orbit, with the vast majority of these only being discovered after the year 2000.

Jupiter’s four largest moons – Ganymede, Callisto, Io, and Europa were discovered by Galileo Galilei in 1610 using an antique version of the present-day telescope and are known the “Galilean moons”. These can be visible from Earth with astronomy binoculars on a clear night.

Three of these four natural satellites (all but Callisto) are known to have multi-layered surfaces comprising a core, mantle, and crust, similar to that of the Earth.

Ganymede is the planet’s largest moon. It is the only moon known to have an internal magnetic field. The limited number of smaller craters on Callisto’s otherwise ancient cratered surface shows that some force is active on this moon. Io is known to be the most active volcanic body in the entire solar system, spewing hot silicate magma and colorful plumes of sulfur.

Europa is believed to have the most favorable environment to foster life. There is evidence that this moon may have large expanses of water (nearly 2 times the water on Earth) just beneath its crust of solid ice. We know that life forms thrive even in the most extreme climatic conditions on Earth, so why not on Europa? We’re yet to find out.

Jupiter’s 69 moons are (in order of diameter, largest (top) to smallest (bottom):

  1. Ganymede
  2. Callisto
  3. Io
  4. Europa
  5. Amalthea
  6. Himalia
  7. Thebe
  8. Elara
  9. Pasiphae
  10. Metis
  11. Carme
  12. Sinope
  13. Lysithea
  14. Ananke
  15. Adrastea
  16. Leda
  17. Callirrhoe
  18. Themisto
  19. Praxidike
  20. Taygete
  21. Iocaste
  22. Kalyke
  23. Megaclite
  24. Chaldene
  25. Isonoe
  26. Helike
  27. Aoede
  28. Eukelade
  29. S/2003 J 5
  30. Hermippe
  31. Thyone
  32. Autonoe
  33. Dia
  34. Harpalyke
  35. S/2016 J 1
  36. Carpo
  37. Hegemone
  38. Euanthe
  39. Aitne
  40. Eurydome
  41. Arche
  42. Erinome
  43. S/2010 J 1
  44. S/2017 J 1
  45. S/2003 J 23
  46. S/2003 J 3
  47. S/2003 J 18
  48. Thelxinoe
  49. S/2003 J 16
  50. Mneme
  51. Herse
  52. S/2003 J 19
  53. S/2003 J 15
  54. S/2003 J 10
  55. Kallichore
  56. Kore
  57. Cyllene
  58. S/2003 J 4
  59. S/2003 J 2
  60. Euporie
  61. Orthosie
  62. Kale
  63. Pasithee
  64. Sponde
  65. S/2011 J 1
  66. S/2011 J 2
  67. S/2010 J 2
  68. S/2003 J 12
  69. S/2003 J 9

When was Jupiter first discovered?

The earliest reports of Jupiter sightings date back to 8th century B.C, with the Babylonians being the first ones to document the experience.

Where does the name “Jupiter” come from?

The planet is named after the king of all Roman gods, Jupiter. In fact, Jupiter is an integral part of several ancient civilizations, each one equating it with their powerful god.

To Mesopotamians, Jupiter was the patron of Babylon, God Marduk. To Greeks, Jupiter was the equivalent of Zeus, God of Thunder. To the tribes of Germany, it represented Thor. In Vedic astrology and Hinduism, the planet represents Brihaspati, teacher of gods. And it is known as “wood star” in Japan, China, and Korea.

Jupiter, thus, enjoys a mythological significance across the world. Interestingly, some of these names reflect the physical nature of the planet as well!

jupiter clouds
Jupiter’s clouds captured by Juno. Image credit: NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstadt/Sean Doran

What missions have humans sent to Jupiter?

Starting in 1973, there have been about eight automated flyby attempts that have provided valuable information about the planet.

NASA’s Pioneer missions saw Pioneer 10 launched in 1972, which was the first space probe to get close to Jupiter, followed by Pioneer 11 in 1973.

Pioneer 10 transmitted over 500 images during the flyby, along with relevant data on the planet’s magnetic field, levels of radiation, Jupiter’s Galilean satellites and several other details, before it continued on its intended interstellar mission, leaving the solar system in 1983.

Pioneer 11 was a robotic probe designed to fly past Jupiter and Saturn, gathering details on the atmosphere, asteroid belt, cosmic rays and other details. This craft transmitted closer images of the Great Red Spot and more information on the polar regions of the planet before proceeding to flyby Saturn and being directed out of the solar system.

Voyager spacecraft 1 and 2 (1977) were deployed to specifically study the outer solar system. Advanced imaging and data-capturing instruments on the probes recorded detailed images and metrics about Jupiter’s clouds and storms and volcanic activity on Io as they moved through the solar system and out of it.

The Ulysses solar probe sent in 1990 later conducted studies on the magnetic fields of Jupiter while on its course to study the Sun’s environment. The probe visited Jupiter twice (1992 and 2004) during its mission. Ulysses mission was a joint exploration venture of NASA and European Space Agency (ESA).

The Cassini probe on its way to Saturn captured impressive images of Jupiter in the year 2000.

The New Horizon’s spacecraft (2006) headed towards Pluto, observed the four largest moons of Jupiter, while also studying the volcanic activity on Io.

While all the above probes simply flew by Jupiter collecting details on the move, NASA’s Galileo probe that was launched in 1989 was the first to orbit the planet for over 7 years, recording a wealth of data and images. A large concentration of hydrogen in Jupiter’s atmosphere, scorching temperatures, and high wind velocities were confirmed from the data. The Galileo probe was intentionally steered into the planet and destroyed to prevent it from colliding with Europa, Jupiter’s only moon with a possibly habitable environment.

The Juno probe that took off in 2011 is designed to study the polar regions of Jupiter, apart from the magnetic and gravitational forces, as well as the composition of its atmosphere/core in greater detail. Juno too will be plunged to destruction once the mission is completed.

Planned explorations to Jupiter

Future explorations reportedly will, among other things, focus on the finding signs-of-life on Europa. ESA’s Jupiter Icy Moon Explorer (JUICE) mission is planned to take off for Europa and Ganymede in 2022, while NASA’s Europa Clipper will be ready to head to Europa in 2025.

Mission Juno – Public Participation

It is now possible for astronomers and astrophotographers to participate in the ongoing Juno mission, by sharing data and images they already hold, joining community discussions, voting on points or features for Junocam to capture and processing raw images from Junocam.

Jupiter facts & statistics

Measure Statistics
Average distance from Earth 748 million km
Average distance from the Sun 778.57 million km
Average surface temperature -145°C
Mass 1.90 × 10^27 kg (316 Earths)
Surface area 6.1419×10^10 km2
Volume 1.4313×10^15 km3 (1300+ Earths)
Diameter 142,984 km (11 x Earth)
Radius 71,492 km
Orbital period 4333 days (roughly 12 Earth years)

References and further information

Here are a few links that offer more information on planet Jupiter:

Read more about the other planets of the Solar System

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