Neptune Archives

August 24, 2023August 24, 2023 by Matt Williams

One of Neptune's Dark Spots Finally Seen From Earth

This image shows Neptune observed with the MUSE instrument at ESO’s Very Large Telescope (VLT). Credit: ESO/P. Irwin et al.

There’s no getting around it: our Solar System’s gas giants all have big, conspicuous spots on their faces. These include Jupiter’s Great Red Spot, Saturn’s Great White Spot, Uranus’ Great Dark Spot, and Neptune’s Great Dark Spot. Far from blemishes or features that tarnish the planets’ natural beauty, these “spots” are caused by massive storms or other processes in the planets’ atmospheres. While they are extremely large by Earth standards, they are difficult to study by anything other than robotic probes that can get close to the planet.

Neptune’s Great Dark Spot was not discovered until NASA’s Voyager 2 probe flew past the planet in 1989 on its way to the edge of the Solar System. Decades later, scientists are still unsure how this storm originated or what mechanisms drive it today. Using the ESO’s Very Large Telescope (VLT), a team of astronomers was able to observe the Great Dark Spot for the first time using a ground-based telescope. Their results provided the most detailed data on the spot to date and some interesting insights into the nature and origin of this mysterious feature.

August 24, 2023August 24, 2023 by Nancy Atkinson

Neptune's Cloud Cover is Linked to the Solar Cycle

This sequence of Hubble Space Telescope images chronicles the waxing and waning of the amount of cloud cover on Neptune. Credits: NASA, ESA, Erandi Chavez (UC Berkeley), Imke de Pater (UC Berkeley)

Whenever Neptune reaches its closest point in the sky to Earth, its portrait is taken by the Hubble Space Telescope and other ground-based observatories. Watching the planet from 1994 to 2020, astronomers have made puzzling discovery.

The clouds in Neptune’s atmosphere appear to be to be linked to the solar cycle and not the planet’s cycle of seasons. The global cloud cover seems to come and go in a cycle that apparently syncs up with the Sun’s 11-year cycle, as it shifts from solar maximum to solar minimum or vice versa. This is surprising since Neptune is so far from the Sun and receives about 0.1% of Earth’s sunlight.

March 20, 2023March 20, 2023 by Laurence Tognetti

The Favorite Solar System Moons of Planetary Geologists; An In-Depth Discussion

The Galilean moons of Jupiter: Io, Europa, Ganymede, and Callisto. (Credit: NASA/JPL-Caltech)

The moons of our Solar System have garnered quite a lot of attention in the last few years, especially pertaining to astrobiology and the search for life beyond Earth. From the Galilean moons of Jupiter to the geysers of Enceladus to the methane lakes on Titan, these small worlds continue to humble us with both their awe and mystery. But do the very same scientists who study these mysterious and intriguing worlds have their own favorite moons? As it turns out, seven such planetary geologists were kind enough to share their favorite Solar System moons with Universe Today!

December 6, 2022December 6, 2022 by Evan Gough

Will We Ever Go Back to Explore the Ice Giants? Yes, If We Keep the Missions Simple and Affordable

Uranus and Neptune are begging to be visited, but expensive missions to visit them may never be approved. Image Credits: (L) By NASA – http://photojournal.jpl.nasa.gov/catalog/PIA18182, Public Domain, https://commons.wikimedia.org/w/index.php?curid=121128532. (R) By Justin Cowart – https://www.flickr.com/photos/132160802@N06/29347980845/, Public Domain, https://commons.wikimedia.org/w/index.php?curid=82476611

It’s been over 35 years since a spacecraft visited Uranus and Neptune. That was Voyager 2, and it only did flybys. Will we ever go back? There are discoveries waiting to be made on these fascinating ice giants and their moons.

But complex missions to Mars and the Moon are eating up budgets and shoving other endeavours aside.

A new paper shows how we can send spacecraft to Uranus and Neptune cheaply and quickly without cutting into Martian and Lunar missions.

November 12, 2022November 13, 2022 by Laurence Tognetti

Will Triton finally answer, ‘Are we alone?’

NASA’s Voyager 2 took this global color mosaic of Neptune’s largest moon, Triton, in 1989. (Credit: NASA/NASA-JPL/USGS)

We recently examined how and why Saturn’s icy moon, Enceladus, could answer the longstanding question: Are we alone? With its interior ocean and geysers of water ice that shoot out tens of kilometers into space that allegedly contains the ingredients for life, this small moon could be a prime target for future astrobiology missions. But Enceladus isn’t the only location in our solar system with active geysers, as another small moon near the edge of the solar system shares similar characteristics, as well. This is Neptune’s largest moon, Triton, which has been visited only once by NASA’s Voyager 2 in 1989. But are Triton’s geysers the only characteristics that make it a good target for astrobiology and finding life beyond Earth?

September 21, 2022September 21, 2022 by Alan Boyle

Neptune and Its Rings Glow in Webb Telescope’s Portrait

JWST view of Neptune and rings — An infrared image from NASA's James Webb Space Telescope shows Neptune and its rings. Credit: NASA / ESA / CSA / STScI / Joseph DePasquale

The first picture of Neptune to be taken by NASA’s James Webb Space Telescope reveals the latest, greatest details of the ice giant’s atmosphere, moons and rings in infrared wavelengths.

Some of those details — for example, faint bands of dust that encircle Neptune — haven’t been brought to light since the Voyager 2 probe zoomed past in 1989.

“It has been three decades since we last saw those faint, dusty bands, and this is the first time we’ve seen them in the infrared,” astronomer Heidi Hammel, an interdisciplinary scientist on the JWST team who specializes in Neptune, said today in a news release. Neptune’s brighter rings stand out even more clearly.

February 8, 2022February 8, 2022 by Brian Koberlein

Why are Neptune and Uranus Different Colors?

A comparison of Uranus (left) and Neptune (right). Credit: Left: NASA/JPL-Caltech, Right: NASA

Uranus and Neptune are similar planets in many ways. Both are ice giant worlds, both have atmospheres rich in methane, and both have a bluish color. But while Uranus has a pale blue-green hue, Neptune has a deep blue color. But why? Why would two planets so similar in size and composition appear so different? According to a recent study, the answer lies in their aerosols.

November 23, 2021November 23, 2021 by Evan Gough

Here are Hubble’s 2021 Photos of the Outer Solar System

The NASA/ESA Hubble Space Telescope has completed its annual grand tour of the outer Solar System for 2021. This is the realm of the giant planets — Jupiter, Saturn, Uranus, and Neptune — extending as far as 30 times the distance between Earth and the Sun. Unlike the rocky terrestrial planets like Earth and Mars that huddle close to the Sun’s warmth, these far-flung worlds are mostly composed of chilly gaseous soups of hydrogen, helium, ammonia, and methane around a packed, intensely hot, compact core. Note: The planets are not shown to scale in this image. Credit: NASA, ESA, A. Simon (Goddard Space Flight Center), and M.H. Wong (University of California, Berkeley) and the OPAL team

If we had to rely solely on spacecraft to learn about the outer planets, we wouldn’t be making great progress. It takes a massive effort to get a spacecraft to the outer Solar System. But thanks to the Hubble Space Telescope, we can keep tabs on the gas giants without leaving Earth’s orbit.

October 17, 2021October 17, 2021 by Andy Tomaswick

Why do Uranus and Neptune Have Magnetic Fields? Hot ice

The outer “ice giant” planets, Neptune and Uranus, have plenty of mysteries. One of the biggest is where exactly they got their magnetic fields. They are strong at that, with Neptune’s being twenty-seven times more powerful than Earth’s, while Uranus’ varies between ? and four times Earth’s strength. Chaos rules in these electromagnetic environments, making them exceptionally hard to both understand and model. Now a team of researchers led by Dr. Vitali Prakpenka of the University of Chicago thinks they might have found the underlying cause of both the field’s strength and its randomness – “hot ice.”

September 30, 2021September 30, 2021 by Andy Tomaswick

Giant Balls of Mush Made From Ammonia and Water Form in the Atmospheres of Uranus and Neptune

One advantage to planetary science is that insights from one planet could explain phenomena on another. We understand Venus’ greenhouse gas effect from our own experience on the Earth, and Jupiter and Saturn share some characteristics. But Jupiter also provides insight into other, farther out systems, such as Uranus and Neptune. Now, a discovery from a spacecraft orbiting Jupiter might have solved a long-standing mystery about Uranus and Neptune – where has all the ammonia gone?