A giant chunk of hail that plunged into the
prairie town of Vivian, S.D., last Friday was confirmed today as the
heaviest hailstone ever recorded in the United States.

The National Climate Extremes Committee, a branch
of the National Oceanic and Atmospheric Administration.
confirmed the weight of a record 1.94 pounds and also a record diameter
(8 inches).

Comet McNaught (C/2009 R1) can be found low in the northeastern sky before dawn gliding through the constellation Perseus. It is brightening as it approaches Earth for a 1.13 AU close encounter on June 15th and 16th. Currently, the comet is at the threshold of naked eye visibility (5th to 6th magnitude) and could become as bright as the stars of the Big Dipper (2nd magnitude) before the end of the month. Estimates are uncertain, however, because this comet is a newcomer to the inner solar system, and thus somewhat unpredictable.

Amateur astronomers Anthony Wesley of Australia and Christopher Go of the Philippines have independently observed an impact event on Jupiter. The strike occurred at 20:31 UT on June 3rd and produced a bright flash of light in the giant planet's cloudtops:

The Atlantic hurricane season is officially under way as of today, and coastal residents are waiting to see if it's as busy as expected. 

Federal government scientists predict that there will be 14 to 23 tropical storms in the Atlantic basin, including 8 to 14 hurricanes.

The National Oceanic and Atmospheric Administration predicts that 3 to 7 of the hurricanes will be major storms that reach Category 3 or higher - meaning they bring sustained winds of at least 111 mph.

NASA's space shuttle program may be winding down, but the US Air Force's is just getting started. On April 22nd, the USAF launched an unmanned mini-shuttle from Cape Canaveral on a secret mission widely thought to involve reconnaissance. The X-37B can now be seen gliding through the night sky shining about as brightly as the stars of the Big Dipper.

In a development that has transformed the appearance of the solar system's largest planet, one of Jupiter's two main cloud belts has completely disappeared.

"This is a big event," says planetary scientist Glenn Orton of NASA's Jet Propulsion Lab. "We're monitoring the situation closely and do not yet fully understand what's going on."

In an article by Claudine Zap on Yahoo!Buzz, she warns not to be alarmed; but high above your heads, a zombie satellite is on the loose.
OK, actually, it won't really be a bother to us earthlings. Or at least
to most of us. (More on that later.) But the rogue communications
satellite is wreaking havoc in Earth's orbit and does threaten to
interfere with signals coming from other satellites. Here's the
backstory...

The communications satellite named Galaxy 15 lost contact with ground control after a solar flare probably fried its brain. As a story from the Christian Science Monitor

The Eta Aquarid meteor shower is the first of two showers that occur each year as a result of Earth passing through dust released by Halley's Comet, with the second being the Orionids. The point from where the Eta Aquarid meteors appear to radiate is located within the constellation Aquarius. Sadly, this location is a bit of a detriment to observers, because this area of this sky only rises an hour or so before morning twilight begins.

According to folklore, this week's full moon has a special name, the Sprouting Grass Moon, because it shines down on the new grasses of northern spring. Go outside after dark and look at the ground. Does the grass look green or blue? The answer may surprise you.

A brand new telescope called the Visible and Infrared Survey Telescope for Astronomy (VISTA) has started observing the cosmos with astonishing results. Located at the ESO's Paranal Observatory, Chile, VISTA has become the world's largest telescope dedicated to mapping the southern hemisphere's sky in visible and infrared wavelengths.

Image: The Flame Nebula inside Orion's Belt. Clearly visible is the famous dark cloud of the Horsehead Nebula. Credit: ESO/J. Emerson/VISTA and Digitized Sky Survey 2.