The disk of the Milky Way Galaxy disk may actually be rippled.
Credit: Heidi Newberg

Two ringlike structures of stars wrapping around the Milky Way’s outer disk now appear to belong to the disk itself.

The results, outlined in a new study, show that the disk is about 60 percent larger than previously thought. Not only do the results extend the size of the Milky Way, they also reveal a rippling pattern, which raises intriguing questions about what sent wavelike fluctuations rippling through the disk.

The researchers said the likely culprit was a dwarf galaxy. It might have plunged through the Milky Way’s center long ago, sparking the rippling patterns astronomers have now detected for the first time. [When Galaxies Collide: Photos of Great Galactic Crashes]

via Size of the Milky Way Upgraded, Solving Galaxy Puzzle.

Jupiter is well-placed for viewing during April 2015. It is in the constellation Cancer all month and can be spotted in the evening sky.
Credit: Starry Night Software

On Saturday and Sunday, you can finish the day by stepping outside and enjoying a view of the rendezvous of two of the brightest objects in the night sky — the moon and the planet Jupiter.

About 45 minutes after the sun sets on both nights, the eye-catching celestial duo will be visible in the southwest sky, roughly two-thirds of the way up from the horizon to the point directly overhead (called the zenith).

The moon will officially reach first-quarter phase on Saturday evening (April 25) at 7:55 p.m. EDT (2355 GMT). The terminator — the line separating the light half of the moon (on the right) from the dark half — will appear perfectly straight, and Jupiter will be about 9 degrees above and to the left of the moon’s left. (Reminder: Your clenched fist held at arm’s length measures about 10 degrees.)

via Moon and Jupiter Rendezvous This Weekend: How to See Them.

(CNN)The massive meteorite split in two shortly before smashing into Earth, wiping out large numbers of species.

The devastating event took place on our planet many millions of years ago, but researchers are only now beginning to discover what happened.

In a remote part of Central Australia, the two pieces of asteroid left what geophysicists say is the largest impact zone ever found on Earth, spreading over an area 400 kilometers (250 miles) wide.

“The two asteroids must each have been over 10 kilometers across — it would have been curtains for many life species on the planet at the time,” said lead researcher Andrew Glikson of the Australian National University.

The team published its research in the journal Tectonophysics this month.

The crater caused by the asteroids vanished long ago. But Glikson said the researchers stumbled across scars from the impacts during drilling for geothermal research.

via Study: Largest ever asteroid impact found in Australia – CNN.com.