A few days ago, NASA announced that on July 19 the Cassini spacecraft was taking a picture of the Earth and the Moon from Saturn’s orbit. On that occasion the agency also launched an initiative inviting people to wave at Cassini and it’s estimated that more than 20,000 people participated. Obviously, from a distance of nearly a 1,5 billion kilometers (about 900 million miles) the Earth is just a dot but it was a symbolic gesture. Almost simultaneously, the MESSENGER spacecraft took a similar picture but from Mercury’s orbit.