Archive · 11 Dec 2025
Monster Stars Shielded Earth 4.4 Million Years Ago
A long time ago, two huge stars zoomed past our Sun.
These stars were much bigger and hotter than our Sun.
They were so close that they would have been very bright in the night sky.
When they passed by, they sent out strong radiation that changed the clouds around our solar system.
This change made the clouds protect our Earth from harmful radiation.
Scientists think this might be why Earth is able to have life.
They figured this out by studying old data and doing computer simulations.
The stars are now far away, about 400 light-years from us.
Two massive stars, Epsilon Canis Majoris and Beta Canis Majoris, flew past the Sun 4.4 million years ago.
The stars were 13 times more massive and much hotter than the Sun, with temperatures of 38,000 and 45,000 degrees Fahrenheit.
Their powerful radiation ionized local interstellar clouds, creating a protective shield for Earth.
The stars were 30-35 light-years from the Sun, making them clearly visible from Earth.
This event may have contributed to Earth's ability to harbor life by shielding it from ionizing radiation.
- Who
- Epsilon Canis Majoris (Adhara) and Beta Canis Majoris (Mirzam)
- What
- Two massive stars flew past the Sun, ionizing local interstellar clouds
- When
- 4.4 million years ago
- Where
- 30-35 light-years from the Sun, in the Canis Major constellation
- Why
- The stars' powerful radiation ionized the clouds, creating a protective shield for Earth
- Stars Involved
- Epsilon Canis Majoris (Adhara) and Beta Canis Majoris (Mirzam)
- Distance from Sun
- 30-35 light-years (281 trillion kilometres)
- Time of Flyby
- 4.4 million years ago
- Stars' Mass
- 13 times more massive than the Sun
- Stars' Temperature
- 38,000 and 45,000 degrees Fahrenheit
- Sun's Temperature
- 10,000 degrees Fahrenheit
- Current Location of Stars
- 400 light-years away