Calculated at around 11,400 earth years.
A year on Sedna is 10,500 Earth years.
No. While we only have a rough estimate of Sedna's size, we know that it is much smaller than Earth.
Sedna's surface gravity is estimated to be 0.27 m/sec2; Earth's surface gravity is about 9.8 m/sec2.
Sedna is thought to be less than 1600 km across, which would make it very much smaller than the Earth. We do not have really good dimensions yet.
The heliosphere starts right here (or, you might say, at the Sun). Sedna is much further out. However, the heliosphere extends far out beyond Pluto. So the outer boundary of the heliosphere can be beyond Sedna. Sedna has an orbit that is very "eccentric" (highly elliptical). It's distance from the Sun varies greatly as it orbits. So, whether Sedna is inside or outside of the heliosphere changes with time.
No. It is much older. Earth is about 4.6 billion years old.
12 years
about 50 years
enouh for 50 years of life
it takes 1 year for the earth to orbit the sun
The earth is estimated to be about 4.55 billions years old.
365 days per year