Sky's Up July-September 2017 - Page 28

Can
solar eclipses be seen on other planets ?

1

Can

solar eclipses be seen on other planets ?

No and Yes . Only Earth is treated by its natural satellite , the Moon , appearing large enough to just cover the Sun without covering much of the sky around the Sun . Some other planets see the Sun “ over-covered ” or way “ under-covered ” by some or all of their natural satellites . Were you to visit any of these places to observe these events , they would look very different from a total eclipse on Earth . If you are interested in the differences and the details , read on . It is first helpful to learn about eclipse and related phenomena here on Earth so you can understand what is described when viewing the events visible on other planets .
Sky ’ s Up
Eclipse Types and the View from Earth The Moon is the only natural satellite in the Solar System that closely matches the apparent size of the Sun in the sky when viewed from the host planet ’ s surface ( or cloud tops , for gas planets ). So , on average , every 1.5 years the Moon will pass in front of the Sun having its apparent size just slightly larger than the Sun . When it blocks the full disk of the Sun , we say we are having a total solar eclipse . Depending on the separation of Earth and Moon and Earth and Sun , a total eclipse can last as long as about 7-1 / 2 minutes and as short as instantaneous , being total for only a split second . You usually won ’ t hear both of the following two eclipse descriptions described as partial eclipses , but they really are . A partial eclipse occurs when the Sun is not completely covered by the Moon . This situation is more common over time because the Moon spends more time farther from Earth than closer to Earth on its elliptical orbit each month . Every eclipse has a partial phase , the only difference
COURTESY OF Steve Edberg
This image shows the Sun ’ s inner (“ lower ”) corona during the total eclipse of March 29 , 2006 , visible from al Saloum , Egypt . Here the Moon has completely covered the Sun , plunging the area and sky into darkness . During this time , the silvery , gossamer corona makes its appearance .
COURTESY OF Steve Edberg
This image shows a partial solar eclipse visible from La Canada High School on October 23 , 2014 . The whole image was too large for the camera sensor so it was cropped to present part of the crescent and the large sunspot group together . This sunspot group is much larger than Earth and is dark because it is 2000C cooler than the surrounding 6000C white light layer that shines on us daily . The silhouette of the Moon is much blacker than the sunspots ; the sunspots are still emitting light but not as brightly as their surroundings . Notice the mountains and valleys visible along the edge of the Moon ’ s silhouette .
15
event spotlight Homestead National Monument of America Located in Beatrice, the Homestead National Monument of America has planned three days of free eclipse festivities. Offerings include presentations from NASA professionals, live entertainment, hands-on activities, science exhibits, and informal stargazing (beginning at 8 p.m. on Aug. 19th and 20th). Events will be held in the park’s Heritage Center and the Ed V6F6VFW"fb6FR4&w&26v67W"6GW&FB7VFBFP&VG&6RV&Ɩ2Ɩ'&'BFRvvP6VGf&w&VG26GW&F@7VFFR'VFw2v&RVg&3FFRFbFRV6Ɨ6RFR'VFw2v&PVg&bFbFW&Rv&R&W6VFF2ƗfRVFW'FVBG27FfFW2B&R'W@FRWfVBv&RFRfWvrЦ&VvrvFf'7B6F7B6'FǐgFW"34EBFRFFV6Ɨ6R&Vv2&VG&6RB"4EBB7G2f""֖WFW2B3P6V6G2f"&Rf&FFPWfVB6Ɩ6W&R#FR&Ɨ7FW&r6RbFR( 2V'&6w2&BV'&66FFƗGvFRV7W&Vǒ#֖WFW2F&6V7BBWBFR7FFRgFW"VFW&r&VBCpEBFS&WBF&BbFRvFFRFFRFRRv&V6P6VG&FƖvBFRFR&R&VF7F&RvVFW"GFW&2bVFЧ&FFVB&VvFBw֖rvfRv2RfRFFRfGFW"FW'&bV'&6RbFR6fW"&WG2FW&2b6VB6fW&vR2Ɩ6R( BFvbW7BfW"SFBvfR"֖WFW2B36V6G2bFFƗGW70ffV7FVB'FRf6Rv2bwVb7GW&RFBwVRFW"'G2bFR7FFRƖ6R2vB66Rf"ff&&RfWvr6FF2FRFv( 2VVP6&VvRGG&7F6VB&RG&wVr6Rf"g&VR'6W'fr'FGFP֖vB&RFW"vB6FF6WBW2&6RBǒffW'2֖WFRBC06V6G2bFFƗG'WBB2FW'7FFRv6V2bRfRFfVR&@vVFW"F22w&VB6RF&RF7VB&RFRFFƗGR6VBFFR6F26VGb7FWF6FVBrFR6VFW&ƖR&WB3֖W0'Fb'FGFRg&FW&RR66"֖WFW2B3B6V6G2`FFƗGBf&WGb6F2RbFW6R2FRv6VGf&w&VG2vW&RFRCF֗766VFW2fWvrv76W2vFW"&GFRBVG'FFP( gFW"FRV6Ɨ6^( &6f"&Rf&F6Ɩ6W&RB#S4EBFR( 26Fr&62WBFR7Vw&B6Bf""֖WFW2B3@6V6G2fWvr6FW2w&B6Bv6ffW'2FRfW&ƗGb'FGFPGVRFG26FV"FW'7FFR6VFR7GV"W6WVbFR&&RVW"Ɩ6v62V'&6( 27FFR6FƖW2vFFR'FW&&&FW"bFPFbFFƗG'WBFR6GvǒfR֖WFRB#B6V6G2VFW"FPV'&&VvrB"4EBV6Ɨ6RvVVVBw&VFW&6V6Ɨ6R6W7FFW2&WGvVVrFCcbf6F'2RFV"vFFP7FFRFFR&FVǒSV'&62FBƗfRvFFRFV'&66FW2FR6VFW&ƖRbFRFbFFƗGƖ6R( "&B( "6v( "6F( "fW( "vG( "vFW"( "w&B6B( "&@( "VFW'6( "V&GB( "Wv7F( "ƗF6fVB( "66G( "vVR6G( "6&V( &fV( "6V( "7FWF( "7FVVW"( "7F6( "F&R&6( "G'( "v&W 4U%DU5b֖6VVW"wwrw&VDW&6V6Ɨ6R6Х6( 0WV'&64U%DU5b֖6VVW"wwrw&VDW&6V6Ɨ6R6Ц60FFƗG&V6W262B"4EBB7WG2V6r֖WFRF7&72FR7FF^( 2'FV7B6&W vFFR6VFW&ƖR6ƗrFgVb6VFW2FVvFR0&Rg&WVVFǒ7V&V7FVBFvVFW 7F&ƗG6VG2FFVBFFV7&V6Pg&֖B&rF֖BgFW&FW&Vf&RFRF֖rf"FFƗGV@W&VrW7B&vBFR6VG`F66v6vfR"֖WFW2@r6V6G2bFFƗG'6W'frWfVG0&R66VGVVBf"&VVF7FR6VvPBFRVƖV&'B''Bǐ&VBVRƗfRFR'&p&BbFFƗGFB2F&Vv62w&VFW&6V6Ɨ6R6W7FFW0&WGvVVb#B#Rf6F'2RFV"vF62F&W6FVG2VrvW&Rg&W70F֖WFRFWF"֖WFW2B36V6G2VFW"FRgVǒ6&VFVB7V6( 0W4U%DU5b֖6VVW"wwrw&VDW&6V6Ɨ6R6Ф626FW2FR6VFW&ƖRbFRFbFFƗGvB( "G&( "vFV#