As you gaze upon a starlit sky it is easy to forget that it is actually a dynamic changing celestial sphere.
To the casual observer, the stars they see tonight were the same as the ones they saw last night and will be approximately the same they will see in ten years time, but look closely and you will see evidence that the Universe is changing and evolving right before your eyes.
A great example is visible to observers in north-eastern United States in the early hours of Thursday morning (20th March) at around 2:06 a.m. ET, when asteroid 163 Erigone will pass directly in front of Regulus, the brightest star in the constellation Leo.
PHOTOS: Cosmic Hotshots from Keck Observatory
Events like these, which are known as occultations, are not terribly rare, but the brightest ones that can be seen with the naked eye are far less common. Regulus, which is the brightest star near the ecliptic, has been occulted by solar system bodies before. Venus occulted the star in 1959, but it will not be until 2044 when the planet occults it again. On Thursday, asteroid 163 Erigone, which is about 72 kilometers (45 miles) wide will pass directly between Earth and Regulus blocking it from our view.