The Discovery of the Galilean Satellites . ... Probably the most significent contribution that Galileo Galilei made to science was the discovery of the four satellites around Jupiter that are now named in his honor. Galileo first observed the moons of Jupiter on January 7, 1610 through a homemade telescope. He originally thought he saw three stars near Jupiter, strung out in a line through the planet. ... Galileo's Observations of Jupiter's Moons . ... Jupiter . ...

Proposal Identification No.: P2681 Date Received: 2011­Oct­03 17:12:34 Technical Page Proposal Type: Followup General Category: Pulsars Observation Category: Galactic Total Time Requested: 60 Hours Minimum Useful Time: 2:30 hours Proposal Title: Followup of PALFA Discoveries ABSTRACT: We propose follow­up observations of 10 new pulsars discovered in the PALFA survey. ... This proposal requires coordination with GPS L3 at 1381 MHz. ...

The weather throughout this year was so extremely favorable that I have been able to observe the Sun clearly on 312 days; however, I counted only 34 groups of sunspots.. From my earlier observations, which I have reported every year in this journal, it appears that there is a certain periodicity in the appearance of sunspots and this theory seems more and more probable from the results of this year.. ... 244 . ... 149 . ... Exploration" home page (index) Glossary . Official GSFC Home Page .. ...

... The weather throughout this year was so extremely favorable that I have been able to observe the Sun clearly on 312 days; however, I counted only 34 groups of sunspots.. From my earlier observations, which I have reported every year in this journal, it appears that there is a certain periodicity in the appearance of sunspots and this theory seems more and more probable from the results of this year.. ... Year . ... Days when no . ... Observation Days . ... 273 . ... 282 . ... 244 . ... 149 . ...

M1 image More About M1 Nice Color Picture . ... M16 image More About M16 HST image . ... M31 image More About M31 Nice Color Picture . ... M42 image ; M43 image More About M42/43 Nice Color CCD Picture . M51 image More About M51 Color Image of M51 M51 Supernova . M57 image More About M57 Nice Color CCD Picture Very Deep M57 Image . ... M81 image More About M81 M81 Supernova Ultraviolet Image of M81 More about Ultraviolet Imaging . M82 image More About M82 M82 False Color M82 True Color . ...

... M31: The Andromeda Galaxy . ... Andromeda is the nearest major galaxy to our own Milky Way Galaxy. Our Galaxy is thought to look much like Andromeda. ... The diffuse light from Andromeda is caused by the hundreds of billions of stars that compose it. ROSAT Explores The X-Ray Sky . ... Caught in the act earlier this summer by the Hubble Space Telescope, the volcanic moon Io (above and right of center) and its shadow (black dot) are seen here against Jupiter's clouds. ...

home publications > mercury . ... Astronomy Beat . ... Nearly four centuries ago, Galileo's simple observations of Earth's planetary sibling, Venus, buoyed the proponents of a Copernican universe. ... The Italian astronomer had settled into a new house in Florence and had begun to observe Venus, which in November 1610 would have appeared as an evening star, bright in the western sky after dusk. ... From these two observations, Galileo inferred that Venus must orbit closer to the Sun than does Earth. ...

Follow-up astrometry and recoveries are made with the ANU 40 inch (1.0-m) f/8 reflector at Siding Spring Observatory (IAU code 413). ... A routine follow-up of 2003 WY153 on 2003 Dec 15 became much more than routine when a faint object with unusual motion vector was found close to the target asteroid. ... During routine astrometry with the 1.0-m to improve the orbit of the Apollo asteroid 2004 CB, the asteroid was found on March 30 to have a short tail! ... Siding Spring Survey Main Page . ...

... Bad Astronomy . ... Bitesize Astronomy . ... Last week's Snack talked about how black holes can affect the environment around them in such a way as to be very bright . ... It's a common misconception that black holes always have matter swirling into them. ... As this matter gets closer and closer to the black hole it piles up and a large, fairly flat disk forms. This is called the accretion disk , because matter from this disk accretes (that is, falls in) on the black hole. ... 2008 Phil Plait. ...

Astronotes Armagh Planetarium's Stellar Blog! ... Planets . ... Earth Satellites . ... A Scorched World: too distant to image, Kepler-10b is depicted here by a NASA artist (Image credit: NASA/Kepler Mission/Dana Berry) . The Kepler satellite looks for planets passing between their parent star and Earth. ... Placed beside our homeworld, Kepler-10b would be about 40% wider than Earth. ... Possibly only occasional jagged islands of metal and rock break the monotony of its glowing lava oceans. ...