Astronomer Eliza Kempton said that she had waited her "entire career" to peer into an atmosphere from this mysterious class of planets.

If the object really is Planet Nine, it would be larger than Neptune and exist 700 times further from the sun than Earth.

Get the facts on this planet of extremes. Orbiting the Sun at a distance of 4.5 billion kilometres - more than 30 times further out than the Earth - Neptune is a dark, icy world. Receiving just one ...