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why are there two high tides in a 24h period when the earth rotates once?

Mark Sterling
Mark Sterling
Research Editor · Feb 16, 2026 · Updated Apr 13, 2026

Because the tides are high when the moon is directly above, or directly on the other side of the world, and lowest when it's 90 degrees to that. This [image](_URL_0_) might help. Obviously, you have the moon overhead once per day, and opposite once per day.

46
Words

1 min
Read Time

#312
of 500 in Space & Astronomy

-32%
vs Category Avg

The Short Answer

Because the tides are high when the moon is directly above, or directly on the other side of the world, and lowest when it's 90 degrees to that. This [image](_URL_0_) might help. Obviously, you have the moon overhead once per day, and opposite once per day.

Analysis

Key Concepts: Moon, directly, tides

This explanation focuses on moon, directly, tides and spans 46 words across 3 sentences. At 32% below the average Space & Astronomy explanation (68 words), the answer takes a direct, no-frills approach — sometimes the simplest explanation is the most effective.

What This Answer Covers

The explanation opens with: “Because the tides are high when the moon is directly above, or directly on the other side of the world, and lowest when “ It then elaborates by explaining the root cause, ultimately building toward a complete picture across 3 connected points.

How This Compares in Space & Astronomy

Ranked #312 of 500 Space & Astronomy questions by answer depth (top 63%). This is in the concise tier — a focused explanation that prioritizes clarity over exhaustiveness. Many readers prefer this level of directness.

Frequently Asked Questions

Is there a simple explanation for why there two high tides in a 24h period when the earth rotates once?

Because the tides are high when the moon is directly above, or directly on the other side of the world, and lowest when it's 90 degrees to that. This [image](_URL_0_) might help. Obviously, you have the moon overhead once per day, and opposite once…

How detailed is this explanation compared to similar Space & Astronomy questions?

This is a focused answer at 46 words, ranked #312 of 500 Space & Astronomy questions by depth. The key concepts covered are moon, directly, tides.

What approach does this answer take to explain there two high tides in a 24h period when the earth rotates ?

The explanation uses root cause analysis across 46 words. It is categorized under Space & Astronomy and addresses the question through 1 analytical lens.