The sun is currently bubbling with activity, with one particularly large sunspot that is associated with strong solar flares.
Very large sunspots can currently be observed on the sun as dark spots, but you should never look straight at the sun without appropriate eye protection.
These dark spots are cooler and therefore emit less visible light than the rest of the surface. The largest spot in this group is about five times the diameter of the Earth and is clearly visible.
Effects of sunspots
The number and size of sunspots are an indication of the sun's activity, which follows a regular cycle. Around every 11 years, the activity oscillates between a fairly quiet phase and a period with significantly more plasma eruptions and strong solar winds.
The last sunspot minimum occurred in December 2019, with the next solar maximum expected around 2025, half a cycle (5.5 years) later.
We are currently in the middle of the 25th sunspot cycle (since 1755) so the current bubbling on the sun is nothing particularly unusual.
That being said, effects can still occur. The increased solar activity can cause so-called solar storms, where large quantities of charged particles are hurled into space, which often hit the Earth's magnetic field.
In particular instances, very strong solar storms can have serious consequences for the technical infrastructure:
Power grids collapse and GPS satellites fail.
Mobile phone networks are disrupted for months.
Blackouts are possible in conurbations, sometimes with losses running into billions.
Radar systems are disrupted and air traffic is affected.
Astronauts have to stay in their spaceships because of the strong radiation.
However these instances are rare and it is estimated that such strong solar storms only "hit" the Earth every 100 to 200 years. More often than not, there are no major problems on Earth and instead they produce beautiful auroras.