People can fall: â  from the edge of a completed roof; â  from the edge where work is being carried out; or â  through openings or gaps. Edge protection Unless the roof parapet provides equivalent safety, temporary edge protection will be required during most work on flat roofs.
Why is astronomy considered the original science? Astronomy is the oldest science for our ancients either drew or made structures according to seasons or movements of celestial bodies in our Universe.
The Sun is the biggest object in our solar system. It contains more than 99% of the solar system's mass. Astronomers think the solar system is more than 4 billion years old. Astronomers are now finding new objects far, far from the Sun which they call dwarf planets.Pluto, which was once called a planet, is now called a dwarf planet.t contains more than 99% of the solar system's mass. Astronomers think the solar system is more than 4 billion years old. Astronomers are now finding new objects far, far from the Sun which they call dwarf planets.