The NASA/ESA Hubble Space Telescope’s Wide Field Camera 3 observed Saturn on 20 June 2019 as the planet made its closest approach to Earth this year, at approximately 1.36 billion kilometres away.
Saturn hosts many recognisable features, most notably its trademark ring system, which is now tilted towards Earth. This gives us a magnificent view of its bright icy structure. Hubble resolves numerous ringlets and the fainter inner rings. Dutch astronomer Christiaan Huygens first identified the rings in 1655 and thought they were a continuous disk encircling the planet, but we now know them to be composed of orbiting particles of ice and dust. Though all of the gas giants boast rings, Saturn’s are the largest and most spectacular.
The age of Saturn’s ring system continues to be debated. And, even more perplexingly, it’s unknown what cosmic event formed the rings. There is no consensus among planetary astronomers today.
Read more here.
This Copernicus Sentinel-1 image takes us just south of the US border, to the region of Baja California in northwest Mexico. Its capital city, Mexicali, is visible top left of the image.
This false colour image contains three separate images overlaid on top of each other. Captured on 30 April, 12 May and 17 June, the different colours represent changes that occurred on the ground.
The Colorado River, which forms the border between Baja California and Sonora, can be seen cutting through the rich and colourful patchwork of agricultural land at the top right of the image, before it fans out and splits into multiple streams. Flowing for over 2300 km, the Colorado River rises in the central Rocky Mountains in Colorado, flows through the Grand Canyon before crossing the Mexican border and emptying into the Gulf of California, also known as the Sea of Cortez.
The Colorado River delta once covered a large area of land and, owing to its nutrients carried downstream, supported a large population of plant and bird life. However today, water that flows is trapped by dams and is used for residential use, electricity generation as well as crop irrigation for the nearby Imperial Valley and Mexicali Valley. The reduction in flow by dams and diversions traps the majority of the river’s sediments before they reach the Gulf of California, impacting water quality.
Copernicus Sentinel-1 is a two-satellite mission, each carrying a radar instrument that can see through clouds and rain. As a constellation of two satellites orbiting 180° apart, the mission can repeat observations every six days, which is also useful for monitoring evolving situations.
This image is also featured on the Earth from Space video programme.
This year’s ambassador of the European Astro Pi Challenge is ESA Astronaut Luca Parmitano. The European Astro Pi Challenge is a school project run by ESA in collaboration with the Raspberry Pi Foundation and gives young people the opportunity to write code that runs on Raspberry Pi computers on board the International Space Station.
Learn everything about this year's Challenge here.
With the climate crisis high on the global political agenda and the issue of greenhouse gases a serious concern, today also saw ESA, the Canadian Space Agency and the Canadian GHGSat company sign a Memorandum of Intent. The new collaboration will entail the provision of free data from the GHGSat constellation to the scientific community and support global efforts to monitor greenhouse gases and improve our understanding of chemical and physical atmospheric processes.
Back row from left to right: Giuseppe Ottavianelli, ESA's Earth Observation Proba-1 and Third Party Mission Manager, Simonetta Cheli, Head of Strategy, Programme & Coordination Office for ESA's Earth Observation Programmes, Johann-Dietrich Wörner, ESA Director General and Adina Gillespie, Director of Business Development, Europe at GHGSat Inc. Front row: Josef Aschbacher, ESA's Director of Earth Observation Programmes and Stéphane Germain, President and Chief Executive Officer at GHGSat Inc.
Read more: ESA's ɸ-week 2019 opens with a flourish
This half-scale model of ESA’s ExoMars Trace Gas Orbiter and the full-scale model of the ExoMars rover below it will be on show during ESA’s Sunday 6 October Open Day at its ESTEC technical centre in Noordwijk, the Netherlands.
Launched in 2016, the Trace Gas Orbiter is today in Mars orbit, seeking out anomalous methane gas in the scant martian atmosphere. The ExoMars rover, named Rosalind Franklin, is due to be launched next year.
The theme of this year’s ESA Open Day is ‘ESA to the Moon’, but ESTEC’s Erasmus Centre will also feature an exhibit called Destination: Mars, highlighting current and future missions to the Red Planet, including plans for an international Mars Sample Return mission.
Australia is tackling multiple bushfires that have broken out across New South Wales and Queensland over the past few days.
In this image captured by the Copernicus Sentinel-2 mission on 8 September, fires burning in the Yuraygir National Park and Shark Creek area are visible. Fires are also burning to the north and south of the villages of Angourie and Wooloweyah. See the image at its full resolution to zoom in on the area.
The flames, which were said to have been whipped up by strong winds, have now been contained. More than 600 firefighters have been deployed to tackle the fires, and multiple homes and outbuildings have been damaged.
Just as people of the same age can vary greatly in appearance and shape, so do collections of stars or stellar aggregates. New observations from the NASA/ESA Hubble Space Telescope suggest that chronological age alone does not tell the complete story when it comes to the evolution of star clusters.
Previous research on the formation and evolution of star clusters has suggested that these systems tend to be compact and dense when they form, before expanding with time to become clusters of both small and large sizes. New Hubble observations in the Large Magellanic Cloud (LMC) galaxy have increased our understanding of how the size of star clusters in the LMC changes with time.
Learn more here.
ESA astronaut Luca Parmitano captured this image of waves in the sky over the Azores, Portugal, from the International Space Station and shared it on his social media channels.
Luca was launched to the International Space Station for his second mission, Beyond, on 20 July 2019. He will spend six months living and working on the orbital outpost where he will support more than 50 European experiments and more than 200 international experiments in space.
First prize of 2019 Φ-week Bootcamp was won by the team PowerPatrol, who came up with an end-to-end demonstrative platform which allows the user to visualise their entire asset network, specify an area of interest, and observe the predicted risk of wildfire by tree contact, with recommended actions based on this risk.
Read more: Winning bootcamp ideas at Φ-week
By studying the rocks inside impact craters like this one, ESA research fellow Joana S. Oliveira has found that the location of Mercury’s magnetic field has changed over time in surprising ways.
Just like Earth, Mercury has a liquid metallic core, the motions within generating the magnetic field. On Earth, our magnetic north and south poles drift between about 10 and 60 km per year, with our planet’s magnetic field orientation flipping more than 100 times in the course of its 4.5 billion years.
Joana used data from NASA’s MESSENGER mission, which orbited Mercury from 2011-2015, to try to better understand the magnetic history of the innermost planet. The results of the study will help inform investigations to be conducted by the joint ESA/JAXA BepiColombo mission that is on route to the planet, arriving in 2025.
Scientists use rocks to study how planets’ magnetic fields evolve. Volcanic rocks created from cooling lava, or rocks that have become molten in large impact events are particularly useful tools. As the rocks cool, any magnetic materials contained with them aligns with the current field, preserving the direction and position of the planet’s magnetic field like a snapshot in time.
Joana and her colleagues used spacecraft observations from five craters with magnetic irregularities. One of the craters, named Rustaveli and found in the northern hemisphere, is pictured here. The craters were suspected to have formed during a time with a different core magnetic field orientation than that of today. The researchers modeled Mercury’s ancient magnetic field based on the crater data to estimate the potential locations for the poles in the past.
They found them to be far from the current position, and could have changed throughout time. They expected the poles to be clustering at two points closer to Mercury’s rotational axis at the geographic north and south of the planet. However, the poles were randomly distributed and were all found in the southern hemisphere. The ancient poles do not align with Mercury’s current magnetic north pole or geographic south, indicating the planet’s dipolar magnetic field has moved. The results also suggest the planet may have shifted along its axis, in an event called a true polar wander, where the geographic locations of the north and south poles change.
While it is not unusual for a planet’s field to change, the new results reinforce the idea that Mercury’s magnetic evolution was very unlike Earth’s. The dual scientific orbiters of the BepiColombo mission will gather unique magnetic field data and potentially narrow the study’s conclusions, while also helping us to place our own planet’s magnetic evolution in context.
The new research is published in the AGU Journal of Geophysical Research.
Read a review of the article on the AGU blog.
Find out more about ESA’s research fellowships (the next application deadline is 1 October).
Things got heated on the International Space Station this week after the Multiscale Boiling experiment, known as Rubi, was successfully switched on.
ESA astronaut Luca Parmitano installed the shoe box-sized container studying the boiling process in the Fluid Science Laboratory of the Columbus module after its arrival on a Dragon cargo resupply mission in August.
The experiment is now in full swing and generated its first bubble under controlled conditions.
While the bubbles form, a number of measurements are taken. The temperature sensor in the left of this image measures bubble temperature while a high-speed camera records how the bubbles behave and an infrared camera tracks the temperature of the heated region.
Scientists will also observe and quantify the effect of external forces on the boiling process.
Rubi is equipped with an electrode to assess the effect of the electric field on the bubbles, as well as a small pump that, when activated, will get the liquid moving to evaluate flow on the boiling process.
Why space bubbles?
Scientists are investigating the boiling process in space mainly for two reasons.
Running this experiment in weightlessness has the advantage that the boiling process takes place in slow motion and the bubbles generated are much larger than on Earth allowing researchers to investigate details of the process in high resolution.
Boiling is a common process in many applications such as refrigeration or cooling of high-performance electronic devices. This research will provide valuable information for designing thermal management systems in a more efficient way, both in space as well as on Earth.
Rubi will run for five months on the International Space Station, during which time more than 600 test runs are planned.
Follow the Rubi experiment on social media for regular updates and more bubbly images and videos.
This image, taken with the NASA/ESA Hubble Space Telescope, focuses on an object named UGC 695, which is located 30 million light-years away within the constellation Cetus (The Sea Monster), also known as The Whale.
UGC 695 is a low-surface-brightness (LSB) galaxy. These galaxies are so faint that their brightness is less than the background brightness of Earth’s atmosphere, which makes them tricky to observe. This low brightness is the result of the relatively small number of stars within them — most of the baryonic matter in these galaxies exists in the form of huge clouds of gas and dust. The stars are also distributed over a relatively large area.
LSB galaxies, like dwarf galaxies, have a high fraction of dark matter relative to the number of stars they contain. Astronomers still debate about how LSB galaxies formed in the first place.
Week in images
9 - 13 September 2019