Why Are Sunspots Darker Than the Surrounding Sun?

💡 The Answer

• Sunspots are cooler regions on the Sun's surface, about 3,000-4,500 K.
• The surrounding photosphere is hotter at about 5,800 K, so it appears brighter.
• Their darkness is an optical illusion of contrast; they would still glow red-hot in isolation.
• Sunspots form where magnetic fields inhibit convective heat flow.