The Earth Story

Astronaut Thomas Pesquet captured this video of the Aurora Borealis outlining the upper atmosphere from the International Space Station.

Astronaut Thomas Pesquet captured this timelapse video of the International Space Station flying past the Aurora Borealis.

Astronaut Thomas Pesquet shared this video flying over the Sahara desert

Video from the Space Station as it flies over Florida (Shrouded in clouds) and the barely-visible behind the clouds Bahamas, with the much lighter blue ocean reflecting off the limestone reef.

Astronaut Thomas Pesquet shared this video of a thunderstorm over central California taken as the International Space Station flies along the coastline. Watch for the light bursts of satellites after the storm passes - next video will show you where they are if you miss them.

Jabal Arkenu

Astronaut Thomas Pesquet captured this view looking down on a mostly cylindrical plateau in southeastern Libya from the International Space Station. The rocks are granitic – the cylindrical shape represents that of a magmatic system beneath a volcano. Above this level, faults would have enabled the overlying crust to move up or down depending on the pressure and magma supply in this body. That crust has since been eroded away, exposing what used to be the core of the magmatic system. The rocks are Eocene in age – formed about 50 million years ago, and as they sit in this site today they are slowly eroding and shedding sediments into the surrounding Kufra basin. That land today is filled with a desert depression; it has alternated between marine and nonmarine settings over the last 100 million years depending on sea level and the rate the land has settled in this area.

-JBB

Image credit: Thomas Pesquet https://flic.kr/p/R62nrJ

References: http://www.fjexpeditions.com/frameset/geography.htm http://www.sciencedirect.com/science/article/pii/S0264817299000136 http://www.peakbagger.com/peak.aspx?pid=11072 https://pubs.usgs.gov/pp/0660/report.pdf (big pdf)

Abstract Art

Astronaut Thomas Pesquet captured this photo of the floodplain of the Dneiper River north of Kiev from the viewing station in the International Space Station in early February with the waters partially covered by snow and ice. The main, largest channel hosts the river that in normal years migrates back and forth by eroding away at its channels, forming a path that becomes gradually more sinuous. Eventually, the channel becomes so sinuous that it breaks through the channel walls and finds a shorter, path, abandoning the arcing meander it formed off to the side. Several of these abandoned, sinuous meanders can be spotted in this photograph – when they are still filled with water they become stagnant and form lakes called “oxbow lakes” (another of my favorite terms).

Interestingly, there’s a pattern of linear streaks from the upper left to the lower right in this image that seems defined only by the white of the snow. I can’t tell if that is an artifact of the motion of the Space Station or of a strong wind direction moving the snow and ice around.

-JBB

Image credit: https://flic.kr/p/QVpSfp

Oxbow lakes and meanders: https://www.youtube.com/watch?v=4qKS_Nk7UmY http://www.mbgnet.net/fresh/lakes/oxbow.htm

Blank dot

Astronaut Thomas Pesquet captured this image of the city of Naples at night from the International Space Station in late January. The dark circle with no streetlights is the outline of the cone of Vesuvius.

Vesuvius last erupted in 1945. In historic times, the volcano has gone through several long periods of inactivity, including a 131-year long period of inactivity during the 16th century. A sudden, major eruption in 1631 brought Vesuvius into a period of activity that lasted 3 centuries. During that period, the volcano’s activity followed cycles of about 20 years, starting with small Strombolian eruptions at its crater and then building into larger explosions before returning to a short period of quiet.

It is unknown how long Vesuvius will take to enter another cycle of activity, nor is it known whether it will awaken with smaller eruptions near its crater or with another large explosion, but both are possible. There are literally millions of people living in this photo’s frame. As a consequence, Vesuvius is one of the most heavily monitored volcanic systems on Earth, but there is still risk. Evacuating 3 million from the Naples Metropolitan area will not be fast or easy, and it is unknown how much of a warning Vesuvius might give. Prior to the 79 AD. eruption there were years of precursor earthquakes before the main blast, but records don’t show a similar long record before the 1631 blast.

-JBB

Image credit: Thomas Pesquet/NASA https://flic.kr/p/R7H8j9

Reference: http://b.gatech.edu/2ki1rbo

Side eye

As the sun sets on 2016 and rises on 2017 for us, it does so as many as 16 times for the astronauts in orbit above our heads on the International Space Station. Astronaut Thomas Pesquet captured and shared this photograph of a colorful sunset on the horizon earlier this month with his camera tilted so the horizon was vertical - because the orbital path of the station is inclined relative to the ecliptic, the position of the horizon can be at a variety of angles depending on exactly where the station is in orbit when the sun slips behind the planet. He suggested it might make a good background photo for your smartphone or tablet in the New Year.

-JBB

Original image: https://flic.kr/p/QfErnG

On twitter: https://twitter.com/Thom_astro/status/815129372973641728

Atmospheric layers

Astronaut Thomas Pesquet captured this photo showing the behavior of the tropopause – the lowermost major boundary in Earth’s atmosphere. In the troposphere, the atmosphere cools down with increasing altitude – this is why when you go up in an airplane or climb a mountain the air outside cools down. At the tropopause, air above begins heating up due to absorbance of UV light from the sun. Temperatures are still below the freezing point of water, but above the tropopause air warms with increasing height. Because of this increase in temperature with height in the stratosphere, called a temperature inversion, clouds and weather from the troposphere rarely penetrate up past the tropopause, and instead spread out at that layer.

The only places in this image where clouds are pushing upwards is at the top of thunderstorms where there is strong upwelling in the atmosphere. Upwelling air at the center of strong storms will overshoot the tropopause, creating clouds that push slightly above that boundary at the center of the upwelling.

-JBB

Image credit: Thomas Pesquet https://flic.kr/p/Pf7xpz

Mountains and cities

Astronaut Thomas Pesquet captured this photo from the International Space Station showing the city of Monterrey, Mexico – that nation’s third largest city. Monterrey tucks up against the edge of the Sierra Madre Orientale mountains and this intergrowth of cities and ridges is a common setup worldwide.

The ridges in this frame are classic fold and thrust tectonics – large sheets of rock are forced upwards along fault planes, leading to elongate ridges at the edge of mountain ranges. These faults create paths that groundwater will flow through, and the mountains often create rainfall as airmasses have to move upwards to pass over them and rising air can trigger rain. Cities, therefore, have a habit of growing right along the edge of mountain ranges because those sites have available water. In fact, the ephemeral Santa Caterina River flows through this city and has cut its way through the easternmost ridge, creating land now occupied by the city.

While tectonics also creates the water supply cities like this rely on, it can also put them in harms way as the same faults that have directed flowing water to spots like these also often rupture, causing earthquakes. As human demands for water increase due to growing population, we see this relationship around the world – people crowd into cities near the foothills of mountains where water is abundant, but that water is abundant in that site because of the forces that create seismic hazards.

-JBB

Image credit: Thomas Pesquet https://flic.kr/p/Q5kfGm

Basic details on the city: http://bit.ly/2hMS1Hs