1 A spokesman says that Russia believes a prototype spacecraft powered by solar sails has been lost because of a malfunction during its launch.
2 Some scientists believe that comets hold the most primitive materials in the solar system and that they played a role in shaping some of the planets.
3 China is cordoning off its own solar market to fend off international competition.
4 The first solar dynamic observatory is expected to be launched no earlier than August 2008.
5 Wind and solar are intermittent power sources - only producing electricity under certain optimum environmental conditions.
6 The comet it had met was itself a visitor from the outer limits of the solar system and the dust particle it shed, and which Stardust caught, have been untouched since the Solar System formed billions of years ago.
7 They hope to show that solar sails could replace traditional rockets and propel spacecraft to the stars.
8 Valles Marineris on Mars is the largest known canyon in the solar system.
9 The solar cell can convert the energy of sunlight into electric energy.
10 One of the four brightest satellites of Jupiter and the eighth in distance from the planet. Originally sighted by Galileo, it is one of the largest satellites in the solar system.
11 The ionosphere is the uppermost part of the atmosphere, distinguished because it is ionized by solar radiation.
12 A few years ago a car fuelled by solar energy would have been inconceivable.
13 The crash of the whole solar and stellar systems could only kill you once.
14 He wondered again about its black color; that was ideal, of course, for absorbing solar energy.
15 There are nine planets in the solar system.