The universe is big, as you can imagine. Even our galaxy is almost beyond comprehension. But measure it we do, at least as best we can.
The most reliable method for making astronomical distance measurements is to use geometry - the 186-million-mile diameter of Earth's orbit is used to construct a baseline of a triangle, much as a land surveyor would use.
When he opened the sixth seal, I looked, and behold, there was a great earthquake, and the sun became black as sackcloth, the full moon became like blood, and the stars of the sky fell to the earth - Revelation 6:12-14
We've only had a few doomsday events come and go in 2014 but a new one arrives April 15th. No, it isn't the IRS, though that is doomsday for American wallets.
Most stars with masses similar to that of our Sun will end their lives as white dwarfs; small, very dense, and hot bodies that slowly cool down over billions of years. On the way to this final phase of their lives the stars throw their atmospheres out into the space and create planetary nebulae, colorful glowing clouds of gas surrounding the small, bright stellar relics.
An captured by ESO's Very Large Telescope (VLT), shows the remarkably round planetary nebula Abell 33, located about 1,500 light-years from Earth. A round appearance is uncommon. Usually something - for example, the way the star spins, or if the central star is one component of a double or multiple star system - disturbs the symmetry and causes the planetary nebula to display irregular shapes.
This week we get Mars in opposition and a bright red planet, but next week is a treat for space enthusiasts also. In the early morning hours of April 15th, north Americans can expect the moon to look a little different.
A total lunar eclipse is expected at this time, a phenomenon that occurs when the Earth, moon and sun are in perfect alignment, blanketing the moon in the Earth's shadow.
An unusual hexagonal shape surrounding Saturn's north pole was spotted on the planet for the first time thirty years ago and nothing similar, with such a regular geometry, has been found on any other (non-Earth, obviously) planet in the Solar System.
That's not the only mystery. Saturn is the only planet in the Solar System whose rotation time remains unknown.
Writing in Geophysical Research Letters, the University of the Basque Country Planetary Sciences Group has now been able to study and measure the phenomenon and, among other achievements, establish its rotation period. What is more, this period could be the same as that of the planet itself.
The Baryon Oscillation Spectroscopic Survey - BOSS - is the largest component of the third Sloan Digital Sky Survey (SDSS-III) and pioneered the use of quasars to map density variations in intergalactic gas at high redshifts, tracing the structure of the young universe.
BOSS charts the history of the universe's expansion and new measures of large-scale structure have yielded the most precise measurement of expansion since galaxies first formed.
Evidence collected over a period of 16 years by NASA's Rossi X-ray Timing Explorer, a satellite in low-earth orbit equipped with instruments that measured variations in X-ray sources, has led to a paper in the Monthly Notices of the Royal Astronomical Society showing huge clouds of gas orbiting supermassive black holes at the centers of galaxies.
Picture a single cloud large enough to span the solar system from the sun to beyond Pluto's orbit. Now imagine many such clouds orbiting in a vast ring at the heart of a distant galaxy, occasionally dimming the X-ray light produced by the galaxy's monster black hole.
The universe is big - really big. Just our Milky Way galaxy alone is about 300 billion stars, with planets whizzing around them and clouds of gas and dust floating in between.
Then there is our orbiting companion, the Andromeda Galaxy and a small group of galaxies in our Local Group, which is about 3 million light years across.
What is in the vast unknown remains a mystery but a recent paper shed light on our immediate neighborhood - bright galaxies within 35-million light years of the Earth.
A new study of gamma-ray light may lead to evidence of dark matter, a hypothetical blanket term for whatever must make up most of the material universe.
Using publicly available data from NASA's Fermi Gamma-ray Space Telescope, scholars at the Fermi National Accelerator Laboratory (Fermilab), the Harvard-Smithsonian Center for Astrophysics (CfA), the Massachusetts Institute of Technology (MIT) and the University of Chicago have created new maps and they believe their maps show that the galactic center produces more high-energy gamma rays than can be explained by known sources.
They believe this excess emission is consistent with some forms of dark matter.
Right now a doomed gas cloud is edging ever closer to the supermassive black hole at the center of our Milky Way galaxy. These black holes feed on gas and dust all the time, but astronomers rarely get to see mealtime in action.
Northwestern University's Daryl Haggard has been closely watching the little cloud, called G2, and the black hole, called Sgr A*, as part of a study that should eventually help solve one of the outstanding questions surrounding black holes: How exactly do they achieve such supermassive proportions?