If the Earth did not have velocity horizontal to the pull of the Sun's gravity, what would happen and why?

The Earth would lose its gravitational pull to the Sun and the planet would slowly detach from our solar system, all plant life on earth would slowly die, due to no sunlight. Our planet (Earth) would slowly decrease in temperature, due to the ultra violet rays of the sun not being present anymore in our atmosphere. And soon all life on Earth would die because all the food would be dead, even the animals because animals need plants to survive