Simulation to create a Milky Way-like galaxy. Supercomputer experiment supports cosmological model of a "cold dark matter" universe After nine months of number-crunching on a powerful supercomputer, a beautiful spiral galaxy matching our own Milky Way emerged from a computer simulation of the physics involved in galaxy formation and evolution.
Hubble Heritage Gallery Images. Out-of-This-World Hypothesis: Cosmic Forces Control Life on Earth. The rise and fall of species on Earth might be driven in part by the undulating motions of our solar system as it travels through the disk of the Milky Way, scientists say.
Two years ago, scientists at the University of California, Berkeley found the marine fossil record shows that biodiversity-the number of different species alive on the planet-increases and decreases on a 62-million-year cycle. At least two of the Earth's great mass extinctions-the Permian extinction 250 million years ago and the Ordovician extinction about 450 million years ago-correspond with peaks of this cycle, which can't be explained by evolutionary theory.
Now, a team of researchers at the University of Kansas (KU) have come up with an out-of-this-world explanation. Their idea hinges upon the fact that, appearances aside, stars are not fixed in space. They move around, sometimes rushing headlong through galaxies, or approaching close enough to one another for brief cosmic trysts.
Galactic bow shock. Active galactic nucleus. Models of the active nucleus[edit] Accretion disc[edit] In the standard model of AGN, cold material close to a black hole forms an accretion disc.
Dissipative processes in the accretion disc transport matter inwards and angular momentum outwards, while causing the accretion disc to heat up. Cosmology - Galaxies. We already met our Milky Way galaxy in the Our Galaxy section.
We also discussed stars which are members of galaxies. Most of the beautiful phenomenon we see in the night sky - comets, planets, star clusters, planetary nebula and diffuse nebula - are all around or within our own galaxy. Seeing Circuits (2) Jan 13, 2005 Seeing Circuits (2) In Part 1 we listed some of the effects of circuits in space and noted that they were all power-consuming effects.
We asked: Where is the power source? The power could be generated locally. The rotational inertia of a body could drive the circuit in much the same way as a water-driven turbine in a dam drives a generator. Early plasma physicists often simply assumed such a mechanism. An electrical current in plasma will generate its own magnetic field and "self constrict" the current channel. Galactic magnetic fields. Introduction Magnetic fields are a major agent in the interstellar medium (ISM) of spiral, barred and irregular galaxies.
They contribute significantly to the total pressure which balances the ISM against gravity. They may affect the gas flows in spiral arms, around bars and in galaxy halos. Magnetic fields are essential for the onset of star formation as they enable the removal of angular momentum from the protostellar cloud during its collapse. MHD turbulence distributes energy from supernova explosions within the ISM. Galactic magnetic fields can be observed in the optical range via starlight which is polarized by interstellar dust grains in the foreground. Cosmic-ray electrons in galaxies, accelerated in supernova remnants or in jets and spiralling around interstellar magnetic field lines with almost the speed of light, emit synchrotron emission over a large range of radio wavelengths.
Galaxies, bar glaxy, the milky way, and our solar system. Zooming Out of our galaxy. Elusive Ancient Galaxy Found. In the Hubble Deep Field Region of the Universe (above), an international team of astronomers managed for the first time to determine the distance of the galaxy HDF850.1, well-known among astronomers as being one of the most productive star-forming galaxies in the observable universe.
The galaxy is at a distance of 12.5 billion light years when the universe was less than 10 percent of its current age. For the past 14 years, HDF850.1 has remained strangely elusive. Its location in space, specifically its distance from Earth – the subject of many studies – ultimately remained unknown. How was that possible? "A vast cloud of dust keeps HDF850.1 hidden from telescopes searching the universe in the visible light range, so even the Hubble Space Telescope can't see it," Robertson said. "Any clue we can get about how those early galaxies formed helps us better understand this process," Robertson said. The galaxy HDF850.1 was discovered in 1998. "Stars form in dense clouds of gas and dust. Galaxy Colonization. Science with Out of this World Info. Daily Galaxy.
The Scale of Things. The Milky Way. Dim Matter. Colliding Galaxies. There are many instances where galaxies appear to be interacting with each other enough to cause obvious distortions of the galaxies that interact.
These interactions may have a significant connections with the manner in which galaxies evolve with time. Example: Arp 273 Interacting Galaxies.