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Mercury

Short answer: Mercury, the closest planet to the Sun, has almost no atmosphere (only a thin exosphere) to trap heat. Its daytime surface reaches about 430 °C (800 °F), hot enough to melt lead, while nights fall to about -180 °C (-290 °F).

That is the largest day-night swing of any planet. Its slow rotation also stretches each day: a solar day lasts about 176 Earth days. Despite the heat, radar and the MESSENGER spacecraft found water ice in permanently shadowed craters near the poles. The footage shows images of Mercury and the Sun, with the presenter.

VideoWrite-up1 sources

In collections:Extreme Cold

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What should you know about Mercury?

Quick facts. Each one stands alone and has a stable ID you can cite.

  1. Mercury has only a thin exosphere.

    DD-133-F01 · Write-up · Exhibit A (No atmosphere)

  2. Days reach about 430 °C.

    DD-133-F02 · Write-up · Exhibit B (430 °C days)

Video transcript: Mercury: Mercury Swings by About 600 °C Between Day and Night

Mercury the closest planet to the sun has extreme temperature variations due to its lack of a substantial atmosphere to retain heat. DID YOU KNOW? During its daytime temperatures can soar up to around 800 degrees Fahrenheit or 430 degrees Celsius, hot enough to melt lead. However, during its nighttime temperatures plummet to approximately 290 degrees Fahrenheit or negative 180 degrees Celsius, making it one of the most extreme temperature differences in our solar system. NOW YOU KNOW!

Burned-in captions, read frame by frame (see transcript.md) · 25.7s Reel ·

Video coming soonMercury · Instagram Reel
Mercury: Mercury Swings by About 600 °C Between Day and Night Instagram Reel · · 25.7s

The write-up

Mercury swings by about 600 °C between day and night. With almost no atmosphere, it can't hold heat.

  1. Exhibit A

    No atmosphere

    Mercury has only a thin exosphere.

  2. Exhibit B

    430 °C days

    Days reach about 430 °C.

  3. Exhibit C

    -180 °C nights

    Nights fall to about -180 °C.

  4. Exhibit D

    Long solar day

    A solar day lasts about 176 Earth days.

  5. Exhibit E

    Polar ice

    Shadowed polar craters hold water ice.

Questions people ask about Mercury

Why can't Mercury hold heat?

Only a thin exosphere.

Source: Write-up · Exhibit A (No atmosphere) · Wikipedia: Mercury (planet)

How hot do days get?

Hot enough to melt lead.

Source: Write-up · Exhibit B (430 °C days) · Wikipedia: Mercury (planet)

How cold do nights get?

About -290 °F.

Source: Write-up · Exhibit C (-180 °C nights) · Wikipedia: Mercury (planet)

How long is a solar day?

Slow rotation.

Source: Write-up · Exhibit D (Long solar day) · Wikipedia: Mercury (planet)

Where is there ice on Mercury?

Found by radar and MESSENGER.

Source: Write-up · Exhibit E (Polar ice) · Wikipedia: Mercury (planet)

Test Your Knowledge

All quizzes →

5 questions, all from this case file. Answers are revealed instantly.

  1. Why can't Mercury hold heat?

    1. It has almost no atmosphere
    2. It's too far out
    3. It has oceans
    4. It's cloudy
    Show the answer

    Answer: A. It has almost no atmosphere Only a thin exosphere. Source: Write-up · Exhibit A (No atmosphere) · Wikipedia: Mercury (planet)

  2. How hot do days get?

    1. About 430 °C
    2. About 43 °C
    3. About 4,300 °C
    4. 0 °C
    Show the answer

    Answer: A. About 430 °C Hot enough to melt lead. Source: Write-up · Exhibit B (430 °C days) · Wikipedia: Mercury (planet)

  3. How cold do nights get?

    1. About -180 °C
    2. About 0 °C
    3. About -18 °C
    4. About -1,800 °C
    Show the answer

    Answer: A. About -180 °C About -290 °F. Source: Write-up · Exhibit C (-180 °C nights) · Wikipedia: Mercury (planet)

  4. How long is a solar day?

    1. About 176 Earth days
    2. 24 hours
    3. 10 years
    4. 1 hour
    Show the answer

    Answer: A. About 176 Earth days Slow rotation. Source: Write-up · Exhibit D (Long solar day) · Wikipedia: Mercury (planet)

  5. Where is there ice on Mercury?

    1. Shadowed polar craters
    2. The equator
    3. Nowhere
    4. Its rings
    Show the answer

    Answer: A. Shadowed polar craters Found by radar and MESSENGER. Source: Write-up · Exhibit E (Polar ice) · Wikipedia: Mercury (planet)

Cite this case file

Easterling, Marcus. "Mercury." The Detail Department (DetailEnjoyer), case file DD-133, last updated Dec 21, 2023. https://detailenjoyer.com/case/mercury/

Permalink: https://detailenjoyer.com/case/mercury/ · Last updated

Markdown version

Cite a single fact by its ID, for example DD-133-F01 → https://detailenjoyer.com/case/mercury/#DD-133-F01

Collection · Extreme Cold Case file 13 of 31

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