Brandon Q. Morris's Blog, page 24

A black-hole Sun: planets could also form around black holes

What does a builder of worlds need to form planets? A protoplanetary disk made out of a suitable material in which differences in density can develop, and an object at the center of the system that acts as a common center of gravity and uses its force of attraction to prevent the cloud of material from floating off into infinity. Until now it had been assumed that these conditions were met primarily by stars. But apparently much more exotic planetary systems are also conceivable, as Japanese...

A place on Earth where everything’s dead

So far, the Earth is the only place in the universe where life has been proven to exist. But even on our planet, there are places that life cannot survive. The geothermal fields in the Ethiopian region of Dallol are one of these places. Near the Danakil Depression in northeastern Ethiopia, close to the border with Eritrea, a volcanic explosion in 1926 formed a crater with a diameter of 30 meters (98 ft), exposing hot salt springs. The emerging water is 70C (158F) and extremely acidic with a...

Fascinating images from the beginning of the universe

Next to theory and experiments, simulations are one of the most important tools used in research today. Occasionally, scientists develop theories that cannot be tested using today’s practice or technology. Here, a simulation might then be able to point the theoretical physicist where he or she needs to look. Other times, it might happen that there are two different theories that could be suitable for describing reality. If simulations are built based on both theories, their results can...

Could an Earth-like planet also survive in an eccentric solar system?

HR5183 is a yellow dwarf star, not very different from our own Sun and located about 103 light-years from Earth. After more than 20 years of observation, astronomers finally found a planet, of about three times Jupiter’s mass, orbiting the star this past summer. Why did it take so long? The planet, HR5183 b, needs 75 years to complete one orbit around its star. Therefore, the period at which it affects the light curve of its star is also correspondingly long.

But what surprised the astronomers eve...

New organic molecules discovered on Saturn’s moon Enceladus

Two years ago, the Cassini probe was sent plummeting into Saturn to its fiery demise – but researchers are still finding new discoveries in the data it sent back. Now, scientists from the Free University Berlin have reported findings from the CDA, the “Cosmic Dust Analyzer,” which was on board Cassini. This instrument was developed in Germany and was designed to study very small particles.

The CDA could detect particles with a velocity of 5 kilometers per second and a mass of only 10

Will our Solar System soon have its sixth dwarf planet?

According to the definition of the International Astronomical Union (IAU), dwarf planets are celestial bodies that do indeed have the round shape of a planet, but do not have sufficient mass to dominate the area around their distance to the Sun. The most well-known example of a dwarf planet is surely Pluto (with a diameter of 2400 kilometers (1490 miles)). Eris, Makemake, and Haumea are three other dwarf planets orbiting in the outer regions of our Solar System. At 950 kilometers (590 miles),...

How much energy can we borrow from a vacuum?

Negative energy doesn’t exist; that’s what we learned in school. If it did, then there’d also have to be negative mass – and thus a repulsive gravitational force, because energy and mass are directly linked with each other, as Einstein showed in his theory of relativity. At the micro-level, however, that’s not true (and that’s one of the reasons why physicists are still having a lot of fun trying to unite relativity and quantum theory). In extremely small areas, it is possible for energy to f...

How a universe made out of fuzzy dark matter might look

The exact composition of 84 percent of all the matter in the universe is unknown. That is the portion, called dark matter, which neither emits radiation nor interacts with conventional matter that we already know of in any other way than through gravity. Cosmologists believe they can use the standard model of the universe, Lambda-CDM, to get to the bottom of dark matter. This model assumes that dark matter is “cold” (cold dark matter – CDM).

In physics, “cold” means that something is moving slowly...

At the end of the Solar System, there’s a surprisingly high pressure

Our Sun emits particles and radiation around the clock. These emissions propagate far into space in all directions and form the heliosphere. At the same time, our Solar System is constantly bombarded from interstellar space by cosmic radiation from a wide range of sources. Way out in the far outer edges of our Solar System, a few billion kilometers from the Sun, these streams of radiation meet each other from both directions in the so-called heliosheath.

The pressure appears to be significantly higher th...

How, not that long ago, the center of the Milky Way exploded

Right now, despite its 4.2 million solar masses, Sagittarius A*, the gigantic black hole at the center of the Milky Way, appears to be a harmless, sleeping giant. But that wasn’t always the case. If one of our ancestors, Australopithecus, had been able to observe the skies over Africa 3.5 million years ago (thus, long after the extinction of the dinosaurs) just as intensively as we can, he might have been able to witness a gigantic, approximately 300,000-year-long explosion in the center of t...