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The solar system – a crash birth

About 4.5 billion years ago, a large cloud of gas and dust collapsed where the solar system is today. Everything that makes up our sun, the planets, moons, asteroids and other celestial bodies in the solar system comes from this cloud. As an international team of researchers led by planetologists from the University of Münster has now discovered, the formation of the entire system took a surprisingly short time: only 200,000 years.

The first solids that formed in the solar system can now be found as micrometer to centimeter-sized inclusions in meteorites. The so-called calcium- and aluminum-rich inclusions (CAIs) provide a direct record of the formation of the solar system. Most CAIs formed 4.567 billion years ago, over a period of about 40,000 to 200,000 years.

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Milky Way’s Family Tree

From small to large: this is one of the possible ways in which structures are created in the universe. Galaxies like our Milky Way are formed when several small predecessor objects join together. But what exactly did the Milky Way form from? An international team of astrophysicists led by Dr. Diederik Kruijssen from the Center for Astronomy at the University of Heidelberg has succeeded in reconstructing the merging history of our home galaxy and creating its family tree. To this end, the researchers analyzed the properties of globular star clusters orbiting the Milky Way.

Globular clusters are dense groups of up to one million stars that are almost as old as the universe itself. The Milky Way is home to over 150 such clusters. “Many of them come from smaller galaxies that later merged to form the Milky Way,” explains Kruijssen. To study the history of fusion, the Heidelberg researcher and his colleague Dr. Joel Pfeffer from Liverpool John Moores University and their research groups developed a series of computer simulations called E-MOSAICS. These simulations comprise a complete model for the formation, development and destruction of globular star clusters.

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Megafloods on Ancient Mars

Surface water or even rain clouds are sought in vain on Mars today. In the early days of the planet, however, things looked different. Four billion years ago, a kind of megaflood could have swept over the Red Planet, as a joint project of scientists from Jackson State University, Cornell, the Jet Propulsion Laboratory and the University of Hawaii shows. It is based on data collected by NASA’s Curiosity Rover, which investigated the Gale Crater on Mars.

In the paper, published in Scientific Reports, the researchers describe how a megaflood – probably triggered by the heat of a meteorite impact that released carbon dioxide ice stored on the Martian surface – caused gigantic waves, revealing geological structures familiar to scientists on Earth. “We identified the megafloods for the first time using detailed sedimentological data,” says co-author Alberto G. Fairén, an astrobiologist. “Deposits left behind by megaflods had not previously been identified with orbiter data”.

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How the universe heats up

Shortly after the Big Bang, in the Planck era, the universe was about 1032 Kelvin hot. Afterwards it expanded rapidly and cooled down as the energy spread over an ever larger space. By and large, this process should continue as long as the universe expands – an end to the expansion is not yet in sight, on the contrary.

But there is a process that counteracts this cooling – at least temporarily. It is easy to understand. When 10,000 people go home from a football stadium, the mood cools down initially as the density of people decreases. But when a few fans get together to celebrate, things get hotter again. The formation of structures is also responsible for the warming of the cosmos. When gas masses clump together with dark matter halos to form galaxies, their particles heat up.

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Where the geysers on Europa could come from

There are several worlds – usually moons – in the solar system, where it appears that life-friendly conditions could exist in the oceans below their crust. Whether this is really the case, we will only know after we have drilled through the ice and checked (as is done in The Enceladus Mission). A new paper by researchers from Stanford University, the University of Arizona, the University of Texas and NASA’s Jet Propulsion Laboratory is now lowering hopes somewhat. As the researchers show, some eruptions may not come from the depths of the oceans, but from water pockets embedded in the ice sheet of Europa.

Using images collected by NASA’s Galileo spacecraft, the researchers developed a model to explain how a combination of freezing and pressurization could lead to a cryovolcano eruption or a water eruption. The results, which were published in Geophysical Research Letters on November 10, have implications for the habitability of the underlying ocean – and could explain geysers on other ice bodies in the solar system. Indeed, if the steam plumes originate from the icy bowl of the moon, they may be less life-friendly because it is more difficult to obtain the chemical energy needed to fuel life there. In this case, the chances of determining habitability from space are also reduced.

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Why the brain and the cosmos are structurally similar

The human brain has a volume of a about one liter (0,26 gallons, man: 1.27 l, woman: 1.13 l), i.e. one cubic decimeter or 0.001 cubic meter. The universe, on the other hand, has a volume of 2.3 million billion trillion cubic light years. Obviously, this is a huge difference of over 30 orders of magnitude. Nevertheless, both structures, the network of galaxies that criss-crosses the universe and the neural network in the brain, have surprising similarities, as Franco Vazza (astrophysicist at the University of Bologna) and Alberto Feletti (neurosurgeon at the University of Verona) note in a paper published in Frontiers of Physics.

The human brain works by means of an extensive neural network, which is thought to contain about 69 billion neurons. On the other hand, the observable universe can count on a cosmic network of at least 100 billion galaxies. In both systems, only 30 percent of the mass is composed of galaxies and neurons. Also in both systems, the elements, neurons or galaxies, arrange themselves in long filaments or nodes between the filaments. Finally, in both systems, 70 percent of the mass and energy distribution consists of components that play an apparently passive role: Water has this role in the brain, whereas dark energy has it in the observable universe.

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Where it rains rocks into magma oceans

Not all rocky worlds resemble the Earth or Mars. If a rocky planet has the bad luck to circle too closely around its star, it becomes an extreme world. Such as the planet K2-141b, which is about 200 light years away from Earth, takes just under 7 hours to orbit around its star K2-141 and orbits only about 1 million kilometers away from it (Earth-Sun: 150 million kilometers). In a study published in the Monthly Notices of the Royal Astronomical Society, scientists from McGill University, York University and the Indian Institute of Science Education have analyzed what the weather cycle of this planet could look like. Evaporation and precipitation of rocks, supersonic winds that rage at over 5000 km/h and a magma ocean at a depth of 100 kilometers are among their conclusions.

“The study is the first to make predictions about weather conditions on K2-141b that can be detected from hundreds of light-years away with next-generation telescopes like the James Webb Space Telescope,” says lead author Giang Nguyen, a PhD student at York University. While analyzing the exoplanet’s illumination pattern, the team discovered that about two-thirds of K2-141b is exposed to constant daylight – more than the hemisphere illuminated by the Sun as we are used to on Earth.

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Salt lakes under the south pole of Mars

Several liquid deposits of different sizes have been discovered by researchers below the south pole of Mars, according to a publication published in Nature Astronomy. The results suggest that there may be lakes below the south pole of Mars that remain liquid due to their high salt concentration.

It is known that subglacial lakes exist in the terrestrial Antarctic. Previous research has shown a similar lake below the southern Martian polar region, which was discovered by the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) on board the spacecraft Mars Express. The presence of a subglacial lake could have important consequences for astrobiology and the presence of habitable niches on Mars. However, there is a debate about whether the water depot is really liquid and how it is composed.

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