When Mercury Crosses the Sun
- Episode aired Apr 28, 1970
On 9 May the tiny planet Mercury will be seen as a black dot in transit across the sun's disc. Because it orbits close to the sun, Mercury has always been difficult to observe, and astronome... Read allOn 9 May the tiny planet Mercury will be seen as a black dot in transit across the sun's disc. Because it orbits close to the sun, Mercury has always been difficult to observe, and astronomers can only guess at the nature of this planet.On 9 May the tiny planet Mercury will be seen as a black dot in transit across the sun's disc. Because it orbits close to the sun, Mercury has always been difficult to observe, and astronomers can only guess at the nature of this planet.