NASA is constantly monitoring the Sun with the Solar Dynamics Observatory (SDO), which is an observation device built specifically for imaging and keeping track of the Sun, its magnetic field, its solar activity, and its sunspots.
Over a 15-day stretch of time from March 7th to March 22nd, NASA’s SDO reportedly observed a period where the Sun was completely spotless, which is an event that generally doesn’t occur all that often.
Image Credit: NASA’s GSFC/SDO/Joy Ng
The SDO capture on the right shows the Sun from March 7th to March 22nd, illustrating how there were no sunspots to speak of.
Related: What would happen if the Sun died?
Sunspots are cooler regions of the star where the magnetic field expands too far and protrudes through the surface of the Sun. This leaves a gap in the star and it slowly fills back in as the Sun’s magnetic field regularizes.
Sunspots are also quite important to scientists, because they can indicate when the sun transitions from one phase to another – in other words, whether the Sun is going through a solar maximum or solar minimum event.
The last time the Sun went through a spotless phase that lasted this long was in April of 2010, which was during a solar minimum. The spotlessness that just recently occurred indicates that the Sun is preparing for yet another solar minimum phase, which NASA estimates will occur between 2019 and 2020.
During a solar minimum, the Sun goes through a temporary period of minimal solar activity. When this happens, the magnetic field calms down and sunspots don’t appear as frequently (or at all). These phases occur regularly every 11 years or so, so while the name may sound daunting, there’s no need to panic; it's just a cycle.
On the other hand, experts have recently predicted 'Maunder Minimum'-like activity from the Sun in the next few decades.
Related: Here's what the Sun looks like at a wavelength of 1.25mm
Source: NASA