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The Sun is the star at the center of our solar system—and the reason Earth can be warm, bright, and habitable. It’s a massive sphere of hot plasma powered by nuclear fusion, and it also drives “space weather” (sunspots, flares, and solar storms) that can affect satellites, radio communications, and power grids.
Below are updated, sourceable Sun facts and statistics for 2026, including the core numbers people search for most: size, temperature, distance, rotation, and the solar cycle.
Sun by the Numbers (2026)
- Type: Main-sequence star
- Age: ~4.6 billion years
- How long it will stay a main-sequence star: ~5 billion more years
- Equatorial radius: 695,500 km (diameter ≈ 1,391,000 km)
- Mass: 1.989 × 1030 kg
- Surface temperature (photosphere): ~5,500 °C
- Core temperature: ~15 million °C
- Average distance to Earth: ~150 million km (1 AU)
- Light travel time to Earth: ~8 minutes
- Rotation period: ~26.8 days (equator) and ~36 days (poles)
- Solar cycle: ~11 years; NASA/NOAA said Solar Cycle 25 reached its maximum phase in 2024
Sources:
NASA Sun Facts |
NASA Sun lithograph (PDF) |
NASA GSFC (1 AU + light travel time) |
NASA (Sun age + main sequence) |
NASA/NOAA solar maximum announcement
Key Sun Metrics Table
| Metric | Value | Notes | Source |
|---|---|---|---|
| Equatorial radius | 695,500 km | Diameter ≈ 1,391,000 km | NASA PDF |
| Mass | 1.989 × 1030 kg | ~99.8% of the solar system’s mass is in the Sun (context) | NASA PDF |
| Composition (by number of atoms) | 92.1% H, 7.8% He, 0.1% other | Values vary by measurement method; this is a commonly cited NASA summary | NASA PDF |
| Surface temperature (photosphere) | ~5,500 °C | The visible “surface” layer is the photosphere | NASA PDF |
| Core temperature | ~15,000,000 °C | Where fusion turns hydrogen into helium | NASA Sun Facts |
| Average distance to Earth | ~149,600,000 km (1 AU) | Earth’s distance varies across its orbit | NASA GSFC |
| Light travel time to Earth | ~8 minutes | Often cited as ~8 minutes (sometimes “8 min 20 sec”) | NASA GSFC |
| Rotation period | 26.8 days (equator); 36 days (poles) | The Sun rotates differentially (not like a solid ball) | NASA PDF |
| Solar cycle | ~11 years | Solar maximum phase announced in 2024 (Cycle 25) | NASA/NOAA |
10 Fun (and Accurate) Facts About the Sun
- It’s mostly hydrogen and helium. A NASA summary lists the Sun’s composition (by number of atoms) as ~92.1% hydrogen and ~7.8% helium. Source
- The Sun’s core is ~15 million °C. That’s hot enough for hydrogen fusion to run continuously. Source
- The visible surface is “only” ~5,500 °C. The photosphere is dramatically cooler than the core—but still far beyond anything on Earth. Source
- The Sun’s diameter is about 1.39 million km. NASA lists the equatorial radius as 695,500 km (so diameter ≈ 1,391,000 km). Source
- Sunlight takes about 8 minutes to reach Earth. That’s based on an average distance of ~1 AU (~149.6 million km). Source
- The Sun doesn’t rotate like a solid object. NASA lists ~26.8 days at the equator and ~36 days near the poles. Source
- It’s a 4.6-billion-year-old main-sequence star. NASA notes the Sun is ~4.6B years old and is expected to remain main sequence for ~5B more years before becoming a red giant. Source
- The Sun’s activity rises and falls on an ~11-year cycle. That cycle changes sunspot counts and the odds of solar storms. Source
- Solar maximum matters on Earth. NASA/NOAA explain that the maximum phase brings increased sunspots and higher chances of solar flares and coronal mass ejections (CMEs), which can affect technology. Source
- You should never look at the Sun directly without proper protection. Even brief exposure can cause permanent eye damage—use certified solar viewers for eclipses and solar observing.
FAQ
How big is the Sun?
NASA lists the Sun’s equatorial radius as 695,500 km, which implies a diameter of about 1.391 million km. Source
How hot is the Sun?
NASA notes the core reaches about 15 million °C, while the photosphere (visible surface) is around 5,500 °C. Source
How far away is the Sun?
The average Earth–Sun distance is ~149.6 million km (1 AU). Source
How long does sunlight take to reach Earth?
About 8 minutes on average (often stated as roughly 8 minutes to 8 minutes 20 seconds depending on rounding and orbital position). Source
What is solar maximum?
Solar maximum is the most active phase of the Sun’s ~11-year cycle, with more sunspots and a higher chance of solar storms. NASA/NOAA announced Solar Cycle 25 reached its maximum phase in 2024. Source
