Astronomy

Question

Why can't we see Uranus,Neptune, and Pluto but we can see Jupiter and Saturn?

Answer

<P dir=ltr style="MARGIN-RIGHT: 0px"><FONT size=3>Great question! I'm assuming that you are actually asking why we can't see the 3 outermost planets with our naked eyes.<BR><BR>The answer has to do with the extreme distances from Earth to these planets.&nbsp; The list below gives the closest that each planet ever gets to the Earth (and most of the time they are much farther away):<BR><BR><FONT face="Courier New">Jupiter&nbsp;&nbsp;&nbsp;0.588 Billion km<BR>Saturn&nbsp;&nbsp;&nbsp;&nbsp;1.2&nbsp;&nbsp; Billion km<BR>Uranus&nbsp;&nbsp;&nbsp;&nbsp;2.47&nbsp; Billion km<BR>Neptune&nbsp;&nbsp;&nbsp;4.3&nbsp;&nbsp; Billion km<BR>Pluto&nbsp;&nbsp;&nbsp;&nbsp; 4.34&nbsp; Billion km<BR></FONT><BR>As you can see, Uranus is more that twice as far away from us as is Saturn, and the&nbsp;last two are almost twice that!&nbsp; Combining the distances involved with the fact that these 3 planets are much smaller than Jupiter and Saturn means that they are not normally visible to the naked eye.<BR><BR>It's not commonly known, but Uranus <STRONG>is</STRONG> visible to the naked eye, under very special circumstances.&nbsp; It has to be when Uranus is making its closest approach to Earth, and the observer has to be somewhere far away from city lights and the atmosphere must be very, very clear and steady.&nbsp; These conditions are so rare that many textbooks simply state that Uranus is not visible to the naked eye.&nbsp; Also, if you know where to look (using a star chart or a planisphere), Uranus is very easy to see through a pair of 7x35 binoculars.<BR><BR>Thanks for asking this question.</FONT></P> http://www.windows.ucar.edu/tour/link=/our_solar_system/solar_system.html http://skyandtelescope.com/observing/skychart/article_1220_1.asp Solar System<BR>Planets<BR>Jupiter<BR>Saturn<BR>Uranus<BR>Neptune<BR>Pluto http://vrd.askvrd.org/services/answerschema.xml