Brandon Q. Morris's Blog, page 29
March 14, 2019
Where are we most likely to find signs of extraterrestrial life?
Today, astronomers know that most stars develop a planetary system during the course of their life. It is estimated that the total number of planets exceeds the total number of stars. On average, each star has between one and two planets. With its 200 billion stars, the Milky Way therefore might have around 300 billion planets.
Of course, there is a huge amount of variability in these planets. There are gas giants that rotate on very tight orbits and are almost as hot as their host star. Ther...
March 10, 2019
How heavy is the Milky Way?
How much does our home galaxy, the Milky Way, weigh? It’s not a very easy task to determine the true dimensions of an object when you live inside that object. Imagine trying to measure the size of your house while sitting at the kitchen table. On top of that, a large part of its mass is not even visible, because it’s dark matter. Scientists estimate there are about 100 to 300 billion stars in the Milky Way. That gives a visible mass of approximately 900 billion Suns at a diameter of 170,000 t...
March 8, 2019
Why does dark matter behave differently in small galaxies than in large ones?
The most important characteristic of dark matter is that it interacts only by way of gravity. And as the only one of the four fundamental forces, gravity is always attractive. Therefore, no matter where it occurs, dark matter must always collect at the mass center of the respective structure, regardless of whether it is a small galaxy or a giant galaxy cluster.
But in reality, things look quite different: in galaxy clusters, dark matter exhibits the expected behavior, but in smaller galaxies...
March 6, 2019
4000 stars: there’s a river of stars flowing through the Sun’s neighborhood
And from the cluster sprang forth a river: that’s not an attempt to be lyrical, just cosmic reality. When stars are born in a star cluster, they often only spend their youth in this group. As time goes on, the entire star cluster starts to feel the effects of gravitational forces from nearby galaxies. Like all stars of the galaxy, the cluster is flung around its core, deforming it over time, with the cluster becoming longer and longer and finally forming a stellar stream – a group of stars tr...
February 25, 2019
Where is the universe hiding its missing mass?
Black makes a person look thin, people like to say. The universe apparently knows this trick too. In any case, it looks significantly skinnier to astronomers than they think it is in reality. Scientists think this because they can calculate how much matter was originally released by the big bang (this refers only to normal matter, not dark matter). If we add up everything that we can see in the sky today, however, we only get to two-thirds of this original amount.
Where is the universe hiding...
February 14, 2019
The universe in your living room: Sega Toys Homestar Flux
How does a science fiction writer best prepare for work? By looking into the universe, of course! Right now, however, it’s not very cozy outside at night, when the curtain has been raised for the universe’s spectacular show, so I bought myself the less-than 200 dollar home planetarium Homestar Flux.
The device comes in well-designed packaging. In addition to the projector, you also receive a USB power cord (handy, because then you can also operate the projector from portable power banks), a s...
February 11, 2019
Dark energy changes over time
Dark energy is thought to be the reason why the universe continues to expand faster and faster, instead of contracting. Yet researchers still don’t have a well-founded theory on what exactly this mysterious form of energy is. If current theories of the universe are correct, dark energy must account for up to 72 percent of the total matter of the universe today.
But what about in the past? Current theory assumes that dark energy had little influence early on. So, the expansion of the universe...
February 8, 2019
Missing member of planetary development discovered in the Kuiper belt
Beyond the orbit of Neptune, at approximately 30 to 50 astronomical units (AU, distance from the Earth to the Sun) from our central star, there are numerous small, medium, and large objects. They form the Kuiper belt – the waste dump for our Solar System, because the matter in this region couldn’t coalesce to form a proper planet. If current theory for planetary development is correct, the belt must contain bodies of all possible sizes.
The problem: first you have to find them. Larger object...
February 1, 2019
No ninth planet after all?
Since around the start of this millennium, astronomers have been actively searching for a planet somewhere out beyond the orbit of Neptune. When Pluto was demoted to a minor planet, “Planet X” became “Planet IX.” At the same time, however, more evidence has been discovered that suggests it does exist. According to the data, a ninth planet should have a mass approximately ten times the mass of the Earth and should orbit the Sun with a semi-axis between 400 and 1500 astronomical units (distance...
January 29, 2019
Heavy stars die in a cocoon
When it’s time for particularly heavy stars to die, they don’t go without a lot of fireworks. If a star that has run out of fuel has a mass greater than 25 times the mass of the Sun, its core will collapse and form a neutron star or a black hole, and gigantic jets of matter will be emitted at its poles. These jets penetrate through the outermost layers of the star and generate so much gamma radiation that astronomers can observe these jets as flashes (Gamma Ray Bursts, GRBs).
This phenomenon...
