Usually, each hemisphere has two main jet streams – a subtropical stream and a stronger polar jet that runs at a lower altitude, though others can form. According to Craig Burke, a senior aviation meteorologist at the Bureau of Meteorology, the wind has to be faster than 100km/h, or it's not a jet stream.Ī vortex within a jet stream on Jupiter recorded in May, 2019 by NASA's Juno spacecraft. The currents form when hot and cold air collide and can reach speeds of more than 440 kilometres per hour.

Much of what we now know about jet streams is credited to bomber pilots flying during WWII, but the phenomenon was first noticed by a Japanese meteorologist in the 1920s and is also found in the gases of Jupiter and Saturn. In Australia flights west to Perth from Sydney or Melbourne will be at least half-an-hour slower than the other way around. In the case of the record-breaking New York to London flight, planes travelling the opposite way took almost three hours longer. They flow from west to east, in line with the Earth's rotation, which is why it's faster to travel in that direction too. They drive the world's weather, acting as conductors on high in the global circulation system. As winds sweep through the upper atmosphere, jet streams are the fast-moving currents carving through their heart. Send us feedback about these examples.Think of a river. These examples are programmatically compiled from various online sources to illustrate current usage of the word 'subsonic.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors.

Sascha Brodsky, Popular Mechanics, 14 Feb.

2023 The team accomplished this feat by using the subsonic-combustion mode during a ground test that simulated a flight at an altitude of 15.5 miles at Mach 6, according to researchers from the National University of Defence Technology in Changsha, Hunan. Kyle Mizokami, Popular Mechanics, The plane performed like no subsonic plane could perform. Emily Mae Czachor, CBS News, 5 June 2023 The use of high-angle, high-speed aeroballistic weapons such as Kinzhal and Iskander-M subsonic, low-altitude Kalibr cruise missiles and low-speed, low-altitude drones, converging from three different directions, was a tactic meant to stress enemy air defenses and the defenders that operate them. Sébastien Roblin, Popular Mechanics, 24 July 2023 Further down on the spectrum are subsonic and transonic, which are used to describe scenarios where objects are traveling either much slower than, or near, the speed of sound. 2023 Bastions units served in mixed brigades-alongside the Bal mobile coastal defense system-using shorter-range, subsonic Kh-35 missiles (81 or 160 miles), which have also been repurposed to attack targets in Ukraine. Sébastien Roblin, Popular Mechanics, 24 Aug. 2023 Such large, subsonic aircraft types aren’t ordinarily intended to fly anywhere close to enemy firepower. Leslie Felperin, The Hollywood Reporter, 3 Sep. 2023 The band’s twangy guitar sounds, droning vocals and loping rhythms mesh perfectly with the often atonal score composed by Trent Reznor and Atticus Ross and sound designer Ren Klyce’s unsettling soundscape, which features subsonic, insectoid rumbles that may induce Havana Syndrome in some viewers. Kyle Mizokami, Popular Mechanics, 5 Sep. Recent Examples on the Web Once the cruise missile reaches subsonic speed, maneuvering fins pop out and the onboard turbine engine takes over propulsion.

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