Meta & Fysikken: Afsnit 54: Brand i den Mexicanske Golf, Ganymedes og Kina I rummet
Idag kommer vi lidt rundt, men meget af dagens afsnit foregår i rummet. Vi vender dog først lige varmerekorden i Canada, samt branden i en gasledning i den Mexicanske Golf. Det er ret vildt! Så kommer vi også ind på Kina og deres fremskridt i rummet. Og hvilken betydning får det mon for vores (menneskets) videre færd i rummet?
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Lidt noter til dagens afsnit:
0. Gas rør i sprunget i den Mexicanske golf og det ligner vandet brænder. Hedebølge i Canada.
1. Wet-bulb temperature:
The wet-bulb temperature is the lowest temperature that can be reached under current ambient conditions by the evaporation of water only. Så det er en temperatur der også forholder sig til fugtigheden.
Even heat-adapted people cannot carry out normal outdoor activities past a wet-bulb temperature of 32 °C, equivalent to a heat index of 55 °C. The theoretical limit to human survival for more than a few hours in the shade, even with unlimited water, is 35 °C.
Cooling of the human body through perspiration is inhibited as the relative humidity of the surrounding air increases in summer.
https://www.popsci.com/environment/wet-bulb-globe-temperature/
The dew point is the temperature to which air must be cooled to become saturated with water vapor. When cooled further, the airborne water vapor will condense to form liquid water (dew). When air cools to its dew point through contact with a surface that is colder than the air, water will condense on the surface.
2. Jupiters store måner. Juno Fly-By.
2.a: Ganymede:
https://www.jpl.nasa.gov/news/see-the-first-images-nasas-juno-took-as-it-sailed-by-ganymede
This is Ganymede, the largest moon in our solar system .
In 2015, NASA's Hubble Space Telescope found the best evidence to date for an underground saltwater ocean on Ganymede. The subterranean ocean is thought to have more water than all the water on Earth's surface.
Jupiter's moon Ganymede is the only moon with its own magnetic field. The magnetic field causes auroras, which are ribbons of glowing, electrified gas, in regions circling the moon’s north and south poles. When Jupiter’s magnetic field changes, the aurorae on Ganymede also change, “rocking” back and forth
Ganymede also has large, bright regions of ridges and grooves that slice across older, darker terrains. These grooved regions are a clue that the moon experienced dramatic upheavals in the distant past!
Ganymede has three main layers. A sphere of metallic iron at the center (the core, which generates a magnetic field), a spherical shell of rock (mantle) surrounding the core, and a spherical shell of mostly ice surrounding the rock shell and the core. The ice shell on the outside is very thick, and about 500 miles (800 kilometers) thick. The surface is the very top of the ice shell. Though it is mostly ice, the ice shell might contain some rock mixed in. Scientists believe there must be a fair amount of rock in the ice near the surface. (Is er lettere end vand hvilket gør at den store måne ikke er så tung. => lav g)
Ganymede's magnetic field is embedded inside Jupiter's massive magnetosphere
Ganymede's grooved terrain probably is the result of tensional faulting or the release of water from beneath the surface. Groove ridges as high as 2,000 feet (700 meters) have been observed and the grooves run for thousands of miles across Ganymede's surface. The grooves have relatively few craters and probably developed at the expense of the darker crust. The dark regions on Ganymede are old and rough, and the dark cratered terrain is believed to be the original crust of the satellite. Lighter regions are young and smooth (unlike Earth's Moon). The largest area on Ganymede is called Galileo Regio
2.b: Expanse:
2.5 x our moon / halvdelen af Jordens Størrelse (altså lidt strørre end Mars). Gravity: 1/7 af jordens.
Gynamede har sit eget magnetfelt.
Mere vand end Jorden.
T= -163°C
Drivhuse, hvor planter gror i vand. Ligesom de store salat fabrikker i Kina.
Vi skal dybt i Isen for ikke at for meget stråling.
0.3 Rem = stråling ved hav overflade på jorden
5-8 Rem= overflade på Gynamede (på trods af magnetfeltet)
Endnu en video:
2.c: Europa re-orienterede sin rotations akse:
Europa's most striking surface features are a series of dark streaks crisscrossing the entire globe, called lineae. Close examination shows that the edges of Europa's crust on either side of the cracks have moved relative to each other.
These various fractures are thought to have been caused in large part by the tidal flexing exerted by Jupiter. Because Europa is tidally locked to Jupiter, and therefore always maintains approximately the same orientation towards Jupiter, the stress patterns should form a distinctive and predictable pattern. However, only the youngest of Europa's fractures conform to the predicted pattern; other fractures appear to occur at increasingly different orientations the older they are.
Europa’s poles are not where they used to be. Cracks in the surface of Jupiter’s icy moon indicate its shell of ice rotated by 70 degrees sometime in the last several million years. In addition to supporting prior evidence for the existence of a subsurface ocean, it also means that the geologic history of Europa’s surface must be reexamined. This can only happen if the icy shell is uncoupled, or floating free, separated from the rocky core of the planet by a liquid water ocean.
NASA's Galileo spacecraft orbited Jupiter from 1995 to 2003 and returned hundreds of images of Europa’s surface. Reconstruction of the global map of Europa at 200-meter resolution in color in preparation for a return to Europa revealed that these mysterious fracture systems were part of the circular true polar wander patterns identified previously. Topographic mapping in the highest resolution images of the fractures at 40 meters per pixel show that the fractures are more than 200 meters deep. The fractures cut through all known terrains and thus show that the deformation related to the global reorientation (or true polar wander) event was one of the last events to occur on Europa. These features also imply that the floating ice shell on Europa may have thickened over time.
Tidal heating occurs through the tidal friction and tidal flexing processes caused by tidal acceleration: orbital and rotational energy are dissipated as heat in the core of the moon, the internal ocean, and the ice crust.
3: Kina i rummet:
I 2019 landede Kina som de første nogensinde på 'den mørke side af månen' - altså den side, som vender væk fra Jorden.
I Dec. 2020 bragte de materiale hjem fra månen, hvilket ikke er sket i 40 år.
Maj måned på Mars: Deres rover har sendt et billede/film (God opløsning)
https://www.space.com/amp/china-mars-rover-zhurong-milestone-took-nasa-decades
Juni (17.) 3 astronauter flyttede in på Chinese Space Station / Tianhe
Fremtiden: Inden for en relativt nær fremtid byder Kinas rumplaner både på rumstationen CSS og et samarbejde med Rusland om at bygge en base på månen.
kilde: