Brandon Q. Morris's Blog, page 23

Strange objects at the center of the Milky Way

Sometimes they behave like a cloud of gas and then they’ll start behaving again almost like an ordinary star: the so-called “G-objects,” which astronomers describe in an article in the scientific journal Nature, are hard to fit into any single category. Six of these objects have already been identified by researchers. They were all found in the direct vicinity of the center of our Milky Way – orbiting the supermassive black hole, Sagittarius A*.

This point of commonality probably also...

Hubble detects small clumps of dark matter

Dark matter holds galaxies together and gives the visible universe its structure. Even though it makes up about five-sixths of all the mass in the cosmos, to date nobody has been able to figure out what it’s made of. On the other hand, there have been some indications about what dark matter is not made of, but researchers still need to determine if dark matter is hot, cold, or possibly even fuzzy, with the temperature designation here referring to the speed at which the particles of dark...

Is the universe repelled by itself?

Does the universe repel itself? That is roughly the idea that researchers from the Immanuel Kant Baltic Federal University in Kaliningrad, Russia proposed in a recent paper. Their paper refers to the Casimir effect, which involves a quantum-physics phenomenon that was predicted and also later confirmed by the Dutch scientist Hendrik Casimir. The Casimir effect causes two conductive plates arranged in parallel in a vacuum to be attracted to each other by a force.

The idea that it might be...

In the early universe, a hydrogen diet made black holes fat

Only a billion years after the big bang, there were already galaxies whose centers harbored supermassive black holes several billion times the mass of our Sun. Astronomers know this from observations of far distant quasars and active galaxies. But how were the black holes able to grow so large so quickly? The problem seemed even more complicated, because earlier observations with ALMA, the Atacama Large Millimeter/Submillimeter Array, had shown a lot of dust and gas in these early galaxies,...

How the ice moon Enceladus got its tiger stripes

Saturn’s ice moon, Enceladus, is one of the most promising worlds in terms of the search for places where extraterrestrial life might exist. Of course, as a reader of the Ice Moon series, you’ve already known that for a long time. Near its south pole there are deep fissures in its crust, through which water is constantly being forced outward. This allows researchers to look under the ice, which is up to 100 kilometers thick, without having to drill through it. A new study tries to explain the...

Three giant black holes at the center of one galaxy

At the center of any galaxy that wants to be taken seriously, a mysterious giant is lurking – a supermassive black hole, often with a mass of millions to billions of solar masses. The center of our Milky Way has a gravitational monster, Sagittarius A*, which has sucked up the mass of more than four million stars the size of our Sun.

But in terms of the universe, that’s almost nothing. Astronomers have now identified three supermassive black holes in the irregular galaxy NGC 6240 as reported...

Hot and cold: an ice giant orbiting a white dwarf

In a few billion years, when our Sun has exhausted its supply of fuel, it will first turn into a red giant and then collapse to form a white dwarf. Some planets of our Solar System will probably survive this time (if they’re not flung out into deep space). Astronomers know this will happen – theoretically. But until now, nobody had ever found a white dwarf with a planet in orbit around it.

So, it’s understandable why researchers are so excited about the discovery of WDJ0914+1914, which is...

When a black hole is simply too big

One of the distinguishing features of black holes is that they are hard to see. Astronomers looking for them sometimes have luck, but at the cost a star: when a ravenous black hole tears off and devours stellar material from an orbiting star, the resulting accretion disk emits radiation that can be measured. Almost all known black holes have been discovered this way.

But it seems logical that those aren’t the only ones out there. Black holes are formed when heavy stars die. And many of these...

How exoplanets develop in multiple-star systems

In the novel, “The Three-Body Problem,” a civilization that developed in a system with three stars plays an important role. This situation has dramatic consequences for the civilization’s planet, which I don’t want to spoil for you. I was reminded of the novel when I read a press release of research work at the University of Jena. Dr. Markus Mugrauer, an astrophysicist there,examined 1300 known star systems with exoplanets to determine how many stars there were within these systems. To do...

Water detected on one of Jupiter’s moons, Europa

The hottest candidates for the development of extraterrestrial life are one of Saturn’s moons, Enceladus, and one of Jupiter’s moons, Europa – even though it’s very cold on its surface. Life, in fact, might be hiding in an underground ocean under the 50-100 kilometer thick layer of ice. Its existence is indicated, among other things, by the countless fault lines criss-crossing across its surface.

Proof of this underground sea, however, has not yet been found. But now, with the help of the...