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Distances

Oort cloud — inner edge: size, dimension and comparison

The adopted reference is about 5.9839E11 km.

diameter of a hypothetical inner boundary ≈ 4 000 AU

598.39 billion km ≈ 598,390 million km. One billion kilometers is 1,000 million kilometers.

The possible beginning of a distant reservoir of comets.

Explore at this scale
Oort cloud — inner edge, interpreted illustration
Interpreted illustration · dimension stated in the fact sheet.

What does this number measure?

This model reference corresponds to twice an inner radius of about 2 000 AU. Estimates for where the Oort cloud begins vary widely, and the cloud has not been directly observed as an envelope. This is a hypothetical boundary, not the cloud's total diameter. The diagram's particles, outlines and density are interpreted.

Compare the stated dimensions

The comparison uses the number in each fact sheet: altitude, height, diameter, length or distance, depending on the reference. Two values in metres do not necessarily describe the same property.

Compare with Sedna’s orbit in the explorer →

Source and limitations

Proposed documented order of magnitude; source linked, not individually audited during this session. Model regions and boundaries are highly uncertain.

Inner edge of the Oort cloud: the diffuse outline of a hypothetical boundary diameter, not the extent of the entire cloud. The haze only suggests the uncertainty of this reference; the points and light are neither bodies to scale nor a density map. The central Sun is symbolic.