Stellar · Solar system
Solar System to Neptune
≈9 billion kmThe broad diameter of Neptune’s orbit reveals how empty a planetary system really is.
Stellar ↔ Stellar
Is M87* wider than the planetary Solar System?
Compare Neptune’s orbital span with the model-dependent diameter of a supermassive black-hole event horizon.
Linear ratio4.222×
Using the stated linear measurements, M87* event horizon is 4.222× Solar System to Neptune.
Stellar · Black holes
M87* event horizon
≈38 billion kmA supermassive black hole whose event-horizon scale rivals the width of the heliosphere.
The answer
A ratio, an analogy and the definitions behind both.
Using the stated linear measurements, M87* event horizon is 4.222× Solar System to Neptune.
About 4.222× Solar System to Neptune linear spans fit across the selected measurement of M87* event horizon.
Neptune-orbit diameter versus Schwarzschild diameter
The metre values can be divided as linear spans, but the two entries do not describe identical kinds of boundary.
Solar System to Neptune is representative; m87* event horizon is model-dependent.
Representative, variable and model-dependent values are useful for perspective only when their status remains visible.
Measurement ledger
What exactly was divided?
| Landmark | Value | Measurement | Certainty | Source |
|---|---|---|---|---|
| Solar System to Neptune | ≈9 billion km | Neptune-orbit diameter | Representative | NASA Science ↗ |
| M87* event horizon | ≈38 billion km | Schwarzschild diameter | Model-dependent | NASA Science ↗ |