A new planet may be being built, not by aliens (well who knows really?), But in a cloud of gas and dust around TW Hydrae about 176 light-years away. This dust and gas cloud is in the constellation Hydra and was spotted by the Hubble space telescope.
A Gap has been detected and current theories point to this being the formation of a new planet. Formation of planets is said to be by the slow pickup of gas and dust eventually becoming, after growing for quite a while, a planet. Unfortunately for the current theories, this planet is being built 7.5 billion light-years from the nearest star, a red dwarf and therefore the gravitational effects of the star are minimal meaning that a planet shouldn’t be being built in this timeframe. TW Hydrae is only 8 million years old and this does not give the correct amount of time predicted by present theories to build a planet (could this be an alien phenomena then? Perhaps the aliens have made created a message.)
An alternative planet theory suggests that a piece of the disk becomes gravitationally unstable and collapses on itself. It is possible that this could create what is seen through Hubble. This would mean a planet could form there in 1000 years.
The James Webb telescope is planned for use to study this particular object in 2018. Perhaps this will come up with an answer?