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How does Earth’s distance from the Sun help maintain its oceans?

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Map graphic showing the boundaries of the five oceans-Pacific, Atlantic, Indian, Arctic, and Southern-using color-coded regions. Four different map projections are included: North Pole view, South Pole view, International Date Line view, and Greenwich Meridian view, each displaying the oceans' extents around the continents. — ocean Earth's oceans and their marginal seas cover nearly 71 percent of the planet's surface.

Earth’s distance from the Sun is a critical factor in maintaining its oceans because it places the planet within the habitable zone, the orbital region where surface temperatures allow water to exist in a liquid state.

If Earth were significantly closer to the Sun, it would experience a runaway greenhouse effect, causing temperatures to rise until the oceans boiled away. Conversely, if Earth were much farther away, solar radiation would be insufficient to maintain surface temperatures above freezing, leading to a global ice-covered state where liquid water could not persist on the surface.

While distance provides the necessary baseline for a clement climate, Earth’s ability to sustain its oceans also relies on its atmosphere, which regulates temperature through the greenhouse effect and prevents the loss of water vapor to space. This delicate balance of solar proximity and atmospheric composition has allowed liquid water to remain a defining feature of Earth’s surface for billions of years.123