Travel the universe with Dr. Ethan Siegel as he answers the biggest questions of all
Neptune holds records in our Solar System, but the Universe gets even faster.
Here on Earth, extreme weather events can cause dramatic wind speed spikes.
When hurricanes are at their most intense, they can reach category 5: with sustained speeds over 157 mph. Here, 2020’s Hurricane Iota is shown with lightning strikes occurring over its eye and to the east/northeast of the system. The frequency of category 3, 4, and 5 hurricanes have been increasing over decadal timescales, likely due to global warming. (NOAA)
Animation of hurricane Ida, shown for August 29, 2021, the day it made landfall in LA. With sustained winds reaching ~155 miles-per-hour and gusts reaching at least ~168 mph, it’s another example of a category 3, 4, or 5 hurricane to make landfall in the last few years. Climate change, most likely, has increased the number of category 3, 4, and 5 hurricanes experienced in the past few decades. (NOAA)
In 2007, Hurricane Felix became one of the most powerful category 5 hurricanes ever measured on Earth, reaching sustained wind speeds of 165 miles per hour (265 kph) and with gusts that achieved even greater speeds. But other planets consist of storms that are larger than the entirety of planet Earth, and possess wind speeds our planet will never attain. (NASA)
In May of 1999, the strongest tornado in terms of maximum wind speed recorded. The Bridge Creek-Moore tornado reached maximum wind speeds of ~484 kph (~302 mph), the fastest winds ever recorded on Earth. 14 years later, in May of 2013, Moore, OK was hit by a tornado once again, which re-devastated much of the same area which had struggled to rebuild when it hit. (VINCENT DELIGNY/AFP via Getty Images)
But Earth’s wind speeds aren’t the Solar System’s highest.
An infrared view of Venus’ night side, by the Akatsuki spacecraft. Its brightness is greater than that of any other planet as seen from Earth, and it approaches our world closer than any other planet does. Measurements of Venus’s atmosphere indicate that its winds have been speeding up, with Venus Express measuring wind speeds of up to ~250 mph, or ~400 kph. (ISAS, JAXA)
In the summer of 2001, which also coincided with Martian summer, a dust storm blanketed the entire red planet. Dust storms can mute or erase virtually all of the surface features we’d otherwise be able to see on Mars, and are most frequent during the relatively warm summers on Mars. However, even at the peak of these storms, they rarely, and barely, exceed wind speeds of ~60 mph. (NASA, J. BELL, M. WOLFF, AND THE HUBBLE HERITAGE TEAM)
As the Huygens probe, launched by Cassini, entered Titan’s atmosphere, it returned this view. At an altitude of ~120 km, it detected wind speeds on Titan that were not only unexpectedly high, but unheard of on that world: up to ~270 mph (around 420 kph), the highest on any terrestrial world other than Earth ever measured. (ESA, NASA, JPL, UNIVERSITY OF ARIZONA; PANORAMA BY RENE PASCAL)
Still, gas giants possess even faster planetary winds.
This video shows an artist’s animation of winds in Jupiter’s stratosphere near the planet’s south pole, with the blue lines representing wind speeds. These lines are superimposed on a real image of Jupiter, taken by the JunoCam imager aboard NASA’s Juno spacecraft. While Jupiter’s winds are typically on the order of 200–400 mph at various altitudes and latitudes, these polar winds can reach ~900 mph: the fastest ever seen on the planet. (ESO/L. CALÇADA & NASA/JPL-CALTECH/SWRI/MSSS)
A false-color animation of Saturn’s hexagon from about 70 individual frames stitched together. This polar vortex is approximately 11 times larger than the central hurricane located directly over the pole, but despite the enormous winds found inside, the upper atmosphere of Saturn’s equatorial regions possess its fastest winds. (NASA/JPL-CALTECH/SSI/HAMPTON UNIVERSITY)
February 23/24, 2011, comparison images of the same storm on Saturn. Images were taken 11 hours (1 Saturn-day) apart, at a resolution of 64 miles-per-pixel. While these storms migrate at substantial speeds, the fastest winds on Saturn are found in the upper atmosphere over its equator, where speeds can reach a maximum of 1100 mph. (NASA / JPL-CALTECH / SPACE SCIENCE INSTITUTE)
Voyager 2 flew by both Uranus (R) and Neptune (L), and revealed the properties, colors, atmospheres, and ring systems of both worlds. They both have rings, many interesting moons, and atmospheric and surface phenomena we’re just waiting to investigate. The biggest unknown difference between the two worlds is why Neptune appears to generate its own heat while Uranus does not. (NASA / VOYAGER 2)
This animated view shows the differential rotation of various layers of Neptune’s atmosphere. The maximum wind speeds are found at high altitudes some ~680 km up in Neptune’s upper atmosphere, where the speeds, which routinely reach 1100 mph, can gust up to 1600 mph at least, the fastest winds of any planet found in the Solar System. (NASA’S GODDARD SPACE FLIGHT CENTER/NASA/JPL)
The fastest winds, however, don’t occur on cold giants.
The observed record? A “hot Jupiter” exoplanet: HD 189733b.
The planet HD 189733b is shown here in front of its parent star. A belt of wind around the equator of the planet travels at 5400mph from the heated day side to the night side. The day side of the planet appears blue due to scattering of light from silicate haze in the atmosphere. The night side of the planet glows a deep red due to its high temperature. (MARK A. GARLICK/UNIVERSITY OF WARWICK)
The change in the red vs. blue character of exoplanet HD 189733b reveals its winds. The relative redshift and blueshift of the eastern and western hemispheres of this world are strong evidence for its atmosphere’s rotation, which shows up in the phase-shifted spectrum of the fast-orbiting, hot exoplanet. With winds of ~5400 mph, it vastly exceeds anything seen in our Solar System. (TOM LOUDEN & PETER J. WHEATLEY, ARXIV:1511.03689)
Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words. Talk less; smile more.
MIT Scientist Jason Soderblom describes how the NASA mission will study the geology and composition of the surface of Jupiter’s water-rich moon and assess its astrobiological potential.
