Water vapor is widely present in the atmosphere, forming clouds that cover most of the planet. It has a composition of primarily nitrogen and oxygen. Inside Earth's crust is a liquid outer core that generates the magnetosphere, deflecting most of the destructive solar winds and cosmic radiation.Įarth has a dynamic atmosphere, which sustains Earth's surface conditions and protects it from most meteoroids and UV-light at entry. Earth's land is part of Earth's crust, consisting of several slowly moving tectonic plates, which interact to produce mountain ranges, volcanoes, and earthquakes. Most of Earth's land is somewhat humid and covered by vegetation, while large sheets of ice at Earth's polar deserts retain more water than Earth's groundwater, lakes, rivers and atmospheric water together. The remaining 29.2% of Earth's surface is land, most of which is located in the form of continental landmasses within one hemisphere, Earth's land hemisphere. Almost all of Earth's water is contained in its global ocean, spanning 70.8% of Earth's surface. This is enabled by Earth being a water world, the only one in the Solar System sustaining liquid surface water. …with binoculars you can see planets, you can see Saturn and Jupiter, you can see Mars with a telescope, the sun and the moon, everything else you see in the solar system is a sphere.Earth is the third planet from the Sun and the only astronomical object known where life developed and found habitability. It’s a useful video for older learners and adults who want to understand the shape of our Blue Marble home, or need to explain it to others.

Aristarchus‘ observations of Earth’s shadow on the moon during lunar eclipses.Eratosthenes‘ measurements of sunlight down wells in two different cities.Looking at ships or boats on the horizon with binoculars.Listen as Thaller describes three observable ways that humans have come to know that we live on a sphere, or specifically, an irregularly-shaped ellipsoid: The ancient Greeks actually had a number of really elegant, wonderful proofs that the Earth was a sphere.

…people have known of this for way more than 2,000 years. So how do we know the Earth is round? Watch this 2018 Big Think explainer: Three proofs that debunk the flat-Earth theory.

Michelle Thaller, astronomer and science communicator with the NASA Goddard Space Flight Center. This is not a viable argument,” explains Dr. “It’s not okay to think that the Earth is flat.

Is the earth round or flat?