California: DJI helicopter drone captures 4K video footage of 'UFO' hurtling across sky

A YouTube user has captured a UFO shooting across the sky at an incredible speed and almost colliding with his helicopter drone in broad daylight in unusually high resolution video footage.

User 1darmino was flying a DJI Inspire 1 unmanned aerial vehicle (UAV) in Silicon Valley that was armed with an ultra HD 4K video camera, and the four-second footage uploaded to YouTube shows a tiny white object hurtling across the sky at a high speed.

In the nine days since the video was uploaded to the video sharing website on 7 March, almost 153,000 users have viewed the footage, and users cannot decide what the mysterious object might be.

Some users think the object could be a bullet, while others believe it could be a lens refraction, a cotton seed in the wind, doctored footage with CGI effects, a supersonic bird, or even an alien spaceship.

What do you think the video is showing? Let us know in the comments below.