Thor experiment

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A sprite seen from the International Space Station. Sprite from ISS.jpg
A sprite seen from the International Space Station.

The Thor experiment aims to investigate electrical activity from thunderstorms and convection related to water vapour transport. The experiment is named as ‘Thor’ after the god of thunder, lightning and storms in Nordic mythology. [1] The experiment is conducted by European Space Agency with a thundercloud imaging system 400 km above Earth.

Thor hammer-wielding Nordic god associated with thunder

In Germanic mythology, Thor is a hammer-wielding god associated with thunder, lightning, storms, oak trees, strength, the protection of mankind, and also hallowing and fertility. Besides Old Norse Þórr, extensions of the god occur in Old English as Þunor, and in Old High German as Donar. All forms of the deity stem from a Common Germanic *Þunraz.

European Space Agency intergovernmental organisation dedicated to the exploration of space

The European Space Agency is an intergovernmental organisation of 22 member states dedicated to the exploration of space. Established in 1975 and headquartered in Paris, France, ESA has a worldwide staff of about 2,200 in 2018 and an annual budget of about €5.72 billion in 2019.



The project analyses electrical activity of thunderstorms by using optical cameras on the International Space Station, ground observations of lightning, and meteorological satellite observations of cloud properties. [2] It is very difficult to capture some of the most violent electric discharges from the ground because the atmosphere blocks radiation. From International Space Station, it will be able to aim the camera, to zoom in and follow interesting regions as the Space Station passes by. The project was initiated by the Danish ESA-astronaut, Andreas Mogensen, and has already delivered valuable data for climate research. [3]

International Space Station Habitable artificial satellite in low Earth orbit

The International Space Station (ISS) is a space station, or a habitable artificial satellite, in low Earth orbit. Its first component was launched into orbit in 1998, with the first long-term residents arriving in November 2000. It has been inhabited continuously since that date. The last pressurised module was fitted in 2011, and an experimental inflatable space habitat was added in 2016. The station is expected to operate until 2030. Development and assembly of the station continues, with several new elements scheduled for launch in 2019. The ISS is the largest human-made body in low Earth orbit and can often be seen with the naked eye from Earth. The ISS consists of pressurised habitation modules, structural trusses, solar arrays, radiators, docking ports, experiment bays and robotic arms. ISS components have been launched by Russian Proton and Soyuz rockets and American Space Shuttles.

More specifically, it studies about the transport of water from the troposphere to the stratosphere, and circulation of the stratosphere and mesosphere driven by internal gravity waves. Convective processes of the troposphere affect the transport of water vapour-a green house gas, and its circulation in both the stratosphere and mesosphere. By analysing the processes that occur in these layers, can improve atmospheric models, and provide a better understanding of Earth’s climate and weather. [4] The experiment also studies how much water the cloud turrets can carry into the stratosphere, and how lightning influences their formation. [1]

Troposphere The lowest layer of the atmosphere

The troposphere is the lowest layer of Earth's atmosphere, and is also where nearly all weather conditions take place. It contains approximately 75% of the atmosphere's mass and 99% of the total mass of water vapor and aerosols. The average height of the troposphere is 18 km in the tropics, 17 km in the middle latitudes, and 6 km in the polar regions in winter. The total average height of the troposphere is 13 km.

Stratosphere The layer of the atmosphere above the troposphere

The stratosphere is the second major layer of Earth's atmosphere, just above the troposphere, and below the mesosphere. The stratosphere is stratified (layered) in temperature, with warmer layers higher and cooler layers closer to the Earth; this increase of temperature with altitude is a result of the absorption of the Sun's ultraviolet radiation by the ozone layer. This is in contrast to the troposphere, near the Earth's surface, where temperature decreases with altitude. The border between the troposphere and stratosphere, the tropopause, marks where this temperature inversion begins. Near the equator, the stratosphere starts at as high as 20 km, around 10 km at midlatitudes, and at about 7 km at the poles. Temperatures range from an average of −51 °C near the tropopause to an average of −15 °C near the mesosphere. Stratospheric temperatures also vary within the stratosphere as the seasons change, reaching particularly low temperatures in the polar night (winter). Winds in the stratosphere can far exceed those in the troposphere, reaching near 60 m/s in the Southern polar vortex.

Thor analyses red sprites, blue and gigantic jets from the Space Station over Earth at night. Sprites appear as luminous reddish-orange flashes and last 20 milliseconds at most. They often occur in clusters within atmosphere above the troposphere at an altitude range of 50–90 km (31–56 mi). They were first photographed on July 6, 1989 by scientists from the University of Minnesota and have subsequently been captured in video recordings many thousands of times. Even though these were discovered only 20 years ago, they hold the key to comprehend the Earth's electrical circuitry that give rise to the storms and currents that churn up the atmosphere. [3] Blue jets can move at speeds of up to 360,000 km/h (220,000 mph) and without a high speed camera they can be easily missed by the human eye. [5]

University of Minnesota public research university in Minneapolis and Saint Paul, Minnesota, United States

The University of Minnesota, Twin Cities is a public research university in Minneapolis and Saint Paul, Minnesota. The Minneapolis and St. Paul campuses are approximately 3 miles (4.8 km) apart, and the St. Paul campus is actually in neighboring Falcon Heights. It is the oldest and largest campus within the University of Minnesota system and has the sixth-largest main campus student body in the United States, with 50,943 students in 2018-19. The university is the flagship institution of the University of Minnesota system, and is organized into 19 colleges and schools, with sister campuses in Crookston, Duluth, Morris, and Rochester.

Data from this experiment could improve the understanding how lightning activity powers cloud turrets, gravity waves, the structure of Transient Luminous Events above thunderstorms. According to Torsten Neubert, of Technical University of Denmark (DTU), the role of thunderstorms in our climate is significant, and Thor will help improve the predictions about the future climate and its consequences. ESA observes that the blue discharges and jets are examples of a little-understood part of our atmosphere and the associated events have implications for how our atmosphere protects us from radiation.”. [6] The images and detailed observations of the flashes were released to the public on January 9 in the journal Geophysical Research Letters . [7] [8]

The Technical University of Denmark, often simply referred to as DTU, is a university in Kongens Lyngby, just north of Copenhagen, Denmark. It was founded in 1829 at the initiative of Hans Christian Ørsted as Denmark's first polytechnic, and is today ranked among Europe's leading engineering institutions.

<i>Geophysical Research Letters</i> journal

Geophysical Research Letters is a biweekly peer-reviewed scientific journal of geoscience published by the American Geophysical Union that was established in 1974. The editor-in-chief is Noah Diffenbaugh.

The Thor experience will team up with the Atmosphere-Space Interaction Monitor (ASIM) experiment on a platform outside the Columbus module in 2017. The ASIM experiment will attempt to observe two ultraviolet optical bands, as well as the X- and gamma-rays, a first for the Space Station. [4]

See also

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  1. 1 2 "Hunting for thunderstorms - iriss mission blog". Retrieved 8 June 2017.
  2. "Demystifying Science — February 12, 2017" . Retrieved 8 June 2017.
  3. 1 2 "Thor: Space Viking Meets Thunder God - DTU Space" . Retrieved 8 June 2017.
  4. 1 2 "NASA - Thor: What Happens Above Thunderstorms?". Retrieved 8 June 2017.
  5. "'THOR experiment' captures rare footage of electrical 'blue jets' in space --". Retrieved 8 June 2017.
  6. "'Thor experiment' captures rare footage of electrical 'blue jets' in space (VIDEO)" . Retrieved 8 June 2017.
  7. "A Godlike Space Mission Found Something Extraordinarily Rare" . Retrieved 8 June 2017.
  8. Chanrion, Olivier; Neubert, Torsten; Mogensen, Andreas; Yair, Yoav; Stendel, Martin; Singh, Rajesh; Siingh, Devendraa (2017-01-09). "Profuse activity of blue electrical discharges at the tops of thunderstorms". Geophysical Research Letters. 44 (1): 496–503. doi:10.1002/2016gl071311. ISSN   0094-8276.