Hard Science Fiction

Jul 29 2022

What saved Earth from the fate of Mars?

Three billion years ago, liquid water existed on Mars as well as on Earth. Today, this is only the case on our home planet. Why is that? Mars no longer has such a strong magnetic field as the Earth. Therefore the solar wind can take the atmosphere better there than here. The magnetic field is generated in the outer core of the Earth, where liquid iron rotates (this is called a "geodynamo"). About 565 million years ago, however, the strength of the magnetic field decreased to 10 percent of its present strength. Then the field mysteriously recovered and regained strength…

Life

Jul 11 2022

News from the cosmic origin of life

Nitriles, a class of organic molecules with a cyano group, i.e. a carbon atom bonded to a nitrogen atom via an unsaturated triple bond, are usually toxic. Yet, paradoxically, they are also an important precursor for molecules that are essential for life - namely, ribonucleic acid (RNA). Astrobiologists already knew that complex molecules are surprisingly common even in space, which is hostile to life. Now, a team of researchers from Spain, Japan, Chile, Italy and the United States has shown that a wide range of nitriles occur in interstellar space in the molecular cloud G+0.693-0.027, near the center of…

Space

Jul 1 2022

What’s hiding near Andromeda?

First there was an amateur astronomer: Giuseppe Donatiello found an interesting "spot" in the Dark Energy Camera data on the 4-meter Víctor M. Blanco telescope. Then, using the larger 8.1-meter Gemini North telescope, the professionals took a closer look and confirmed that the object, then named Pegasus V, was an ultra-faint dwarf galaxy on the edge of the Andromeda Galaxy. The observations revealed that the galaxy appears to be extremely poor in heavier elements compared to similar dwarf galaxies, which means that it is very old and probably represents a fossil of the first galaxies in the universe. In…

Life

Jun 28 2022

Worlds quite different from Earth could also harbor life

Are our ideas of the habitable zones around a star too Earth-centric? Of course. We've only found one example of life in the universe so far, so we all draw conclusions. But there are alternatives, as researchers from the University of Bern and the University of Zurich have just reported in a study published in the journal Nature Astronomy. According to the study, favorable conditions could even prevail for billions of years on planets that barely resemble our home planet. "One of the reasons water can be liquid on Earth is its atmosphere," explained study co-author Ravit Helled, professor…

What NASA is up to in the clouds of Venus

Space

Jun 9 2022

What NASA is up to in the clouds of Venus

In nine years (2031), our hot neighboring planet Venus will be visited by NASA's DAVINCI mission (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging). In a paper, the scientists and engineers involved have now explained what the probe is supposed to do. As its name suggests, it is primarily concerned with the planet's dense atmosphere, in which - unlike on the hot surface - conditions are expected to be favorable even for life. Davinci is therefore primarily a flying chemistry laboratory. Due mission consists of an orbiter (CRIS, carrier, relay and imaging spacecraft) and a lander. The…

Why Uranus and Neptune are colored differently

Space

Jun 7 2022

Why Uranus and Neptune are colored differently

Actually, Uranus and Neptune, the two outer planets of the solar system, are quite similar. Known as the "ice giants," the planets have similar masses (14.5 to 17 Earth masses), sizes (51,000 to 49,000 km at the equator), and atmospheric compositions (hydrogen at around 80%, helium around 15%, methane about 2%) - and yet they differ significantly in appearance. In the visible wavelength range, Neptune has a rich, deep blue hue, while Uranus has a much paler cyan hue. Astronomers have now found and published an explanation for the different colors of the two planets. The researchers refer to…

Astrophysics

May 29 2022

How heavy are the stars?

R136a1 is currently the heaviest known star. It weighs as much as 265 suns. Most stars, however, are much smaller and lighter - down to about one tenth of the mass of the sun. Celestial bodies that have accumulated too little gas cannot ignite nuclear fusion and remain brown dwarfs. Supergiants like R136a1, on the other hand, glow intensely but die young. How heavy are the stars of the universe on average? This is described by the so-called primordial mass function. It says that heavy stars are much rarer than light ones. So the universe is likely to be…

Does a hidden mirror universe influence our world?

Astrophysics

May 21 2022

Does a hidden mirror universe influence our world?

One of the fundamental parameters of our universe is the Hubble constant H0. It indicates the speed with which distant objects move away from us and thus determines the fate of the entire universe. Today we know that it is not a constant in the strict sense, since H0 changes with time. However, science has a fundamental problem with it. Depending on how it is measured, its value differs. The difference between the measurement methods even grows the more precise the measurements are. If H0 is calculated from the standard model of cosmology (Lambda Cold Dark Matter, ΛCDM), the…