ផែនដី
Our home: the only world known to have life and liquid water oceans on its surface.
NASA
The only world we know of with oceans on its surface, a breathable atmosphere and life.

Earth is the largest and densest of the rocky planets. About 71% of its surface is covered by oceans, and its nitrogen-oxygen atmosphere and magnetic field shield life from much of the Sun’s harmful radiation.
Its spin axis is tilted about 23.4° to its orbit, which causes the seasons. It has one natural satellite, the Moon. The orbit data here are for the Earth-Moon barycentre, the balance point of the pair.
ផ្កាយព្រះច័ន្ទក្នុងមូលដ្ឋានចំណេះដឹង
ប្រភពទិន្នន័យ
Tools and lessons use simplified models for learning only. They must not be used for navigation, mission planning or any operational decision. Certificates are free and non-accredited. អានការលុបចោលមាតិកាអប់រំ