Astronomers Daily

Look upward at the night sky and you're viewing the stars of the Milky Way galaxy as they were hundreds and even thousands of light-years in the past. The time it takes the starlight from these celestial bodies to travel the distance between these stars and Earth is very long in human terms, despite the speed of light. If astronomers indicate that a particular galaxy is sixty-million light-years away from Earth, this means it takes light sixty-million light-years to travel the distance to Earth from this galaxy. The true environments existing in distant galaxies remains a mystery for the moment. We'll board our time-machine-to-the-stars tonight and journey to the beginning of the universe to take a look a look at the local group of galaxies within the gigantic wheel of the Virgo Supercluster. The physical reality existing in these distant galaxies is likely to be unlike anything imaginable by humankind and things out among distant galaxies doesn't work as you have been taught things work on Earth. Travelers unfamiliar with Einstein's relativity need to bone-up on special and general relativity, before getting on board, this will help you deal with the realities of your journey to the beginning of the universe.

Astronomers looking upward into the night sky realised centuries ago that deep-sky objects are distributed unevenly about the night sky. French comet hunter Charles Messier (1730-1817) looking upward into the night sky through his time-machine-to-the-stars compiled a popular catalog of deep-sky objects. His catalogue contains high concentrations of deep-sky objects within the Milky Way above you, where open star clusters and star-forming areas that form them congregate.

Messier's catalogue also contains entries on 16 objects he located near the border between the constellations Virgo and Coma Berenices. Star gazer William Herschel (1738-1822) and his son, John Herschel (1792-1871), recorded more than 200 celestial objects in this same region of the night sky. It would be in the 1920s and 1930s that astronomers would determine that these nebulous objects are in fact galaxies as big, or larger than, the Milky Way galaxy that constitute a cluster of galaxies far beyond the Milky Way.

Two decades later, French-born astronomer Gerard de Vaucouleurs (1918-1995) noted that the halo of galaxies surrounding what astronomers referred too as the Virgo cluster actually extends all the way to our Local Group of galaxies, which the Milky Way calls home. Today astronomers refer to this Local Group of galaxies as our Local Supercluster of galaxies.

Presently, astronomers believe our Local Supercluster extends 50 million light-years, from the center of the Virgo cluster. We'll journey from the center of our Local Group to slightly beyond the Virgo cluster. Along the way we'll stop at all of the galaxy groups and clusters containing at least three reasonably large galaxies and see what astronomers have determined about these distant celestial bodies in the night sky above you.

The first celestial object in the night sky we'll journey to see is called the Ursa Major North Group, next we'll travel to Ursa Major South Group, and then make our way to each of the galaxy groups and clusters in the Milky Way's Local Group of neighbors.

Neutron star SGR 0418+5729 shows off

The human journey to the beginning of the universe discovered another neutron star on June 5, 2009 that's currently keeping astronomers and space scientists busy looking into the unusual properties of this newest member of the pulsar zoo. Astronomers using NASA’s Chandra, Swift and Rossi X-ray observatories, the Fermi Gamma-ray Space Telescope and ESA’s XMM-Newton telescope have been taking a look at this slowly rotating neutron star with an ordinary surface magnetic field as it gives off x-rays and gamma rays. Astronomers think the facts they have collected during their study of neutron star SGR 0418+5729 could indicate the presence of an internal magnetic field much more powerful than the surface magnetic field of this pulsar. This has definite implications in relation to the evolution of the most powerful magnets we have observed during the human journey to the beginning of the universe and astronomers are now delving into the mysteries they see within this neutron star to determine the facts.

Astronomers looking at neutron star SGR 0418+5729 think this pulsar is one of a strange breed of neutron stars they refer too as magnetars, which normally have strong to extreme magnetic fields 20 to 100 times above the average for galactic radio pulsars they have viewed in the universe. What really has astronomers viewing SGR 0418+5729 scratching their heads is the fact that over a 490 day period of observing this pulsar astronomers saw no detectable decrease in this neutron stars rotational rate. Astronomers think that the lack of rotational slowing of this neutron star could mean that the radiation of low-frequency waves is pretty weak, which leads them to believe the surface magnetic field of this pulsar must be quite a bit less powerful than normal. This conclusion gives astronomers another puzzle to solve, since with this thought astronomers are wondering where the energy for this neutron stars power bursts and x-ray emissions come from. Does the power and energy creating this neutron stars power bursts and x-ray emissions originate in the twisting and amplifying of this pulsars internal magnetic field in the chaotic interior of this neutron star? Present theories on this indicate that astronomers believe that if the internal magnetic field becomes ten or more times stronger than the surface magnetic field, the twisting or decay of the magnetic field could lead to the production of steady and bursting x-rays through the heating of the pulsar's crust or the acceleration of particles in the magnetic field. The question astronomers want to answer now is how large can the imbalance between the surface and interior magnetic fields be? If further observations indicate that the surface magnetic field limit is pushed to low, then astronomers will have to dig a little deeper into SGR 0418+5729 to find out why this neutron star is rotating slower.