A mysterious piece of object nicknamed "WTF" is headed towards Earth, but astronomers are still wondering what exactly this aptly named space object is.

The approaching unknown object, called WTF1190F, is projected to crash on Nov. 13 in the Indian Ocean, specifically around 40 miles (65 km) off the southern tip of Sri Lanka.

Although researchers are still figuring out what the object is, they have determined that it measures up to 7 feet (2 metres) long.

Most space scientists believe that WTF may be a part of a spacecraft from the Apollo programme craft which has been floating in space for more than 40 years.

Other scientists believe that the mysterious object is a part of a rocket stage from a recent lunar mission.

If these predictions turn out correct, WTF1190F will be the first piece of man-made space junk to return home independently.

The space debris also seems to be hollow, according to space researchers, evidenced by the fact that it is travelling in an elliptical orbit, with its longest point twice as long as the distance between Earth and the moon.

The European Space Agency's (ESA) Near Earth Object office has already assigned space scientists in Noordwijk, the Netherlands, to closely monitor the space junk's journey.

Bill Gray, an independent astronomy software developer who has been tracking WTF1190F through the National Aeronautics and Space Administration (NASA)'s Jet Propulsion Laboratory in Pasadena, California, nevertheless assured that the space junk will not bring catastrophic events to planet Earth.

The debris will likely dissipate and disintegrate upon entering the atmosphere, Gray predicted.

However, he warned against doing activities near the space junk's predicted crash site.

"I would not necessarily want to be going fishing directly underneath it," Gray said, as quoted by The Daily Mail.

Instead of fearing the space junk, space scientists will actually use WTF1190F to test their capacities to prevent similar objects from directly colliding with Earth.