-4
$\begingroup$

Why does Earth still have an active, Hot interior core, but Mars and Venus have none?

$\endgroup$

closed as off-topic by stafusa, Jon Custer, Kyle Kanos, glS, JMac Dec 18 '17 at 13:14

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "Homework-like questions should ask about a specific physics concept and show some effort to work through the problem. We want our questions to be useful to the broader community, and to future users. See our meta site for more guidance on how to edit your question to make it better" – stafusa, Jon Custer, glS, JMac
If this question can be reworded to fit the rules in the help center, please edit the question.

  • 3
    $\begingroup$ How does the title relate to the question? $\endgroup$ – Dmitry Brant Dec 17 '17 at 19:48
  • 2
    $\begingroup$ This question posits something that is false. Mars has a hot, partially molten core. Venus almost certainly does, too. What Venus and Mars don't have is plate tectonics. $\endgroup$ – David Hammen Dec 17 '17 at 20:09
  • $\begingroup$ Not "Earth's gravitational Field", but rather, "Earth's Magnetic Field" relative to Mars and Venus. In other words, without a hot turbulent core, there can be no Magnetic Fields on these two planets. Do they have Magnetic Fields? If not, Why? $\endgroup$ – Douglas D. Beatenhead Dec 18 '17 at 15:35
2
$\begingroup$

Why does Earth still have an active, hot interior core, but Mars and Venus have none?

This is incorrect. Mars and Venus almost certainly have hot molten outer cores, just as does the Earth. The evidence for this lies in the time variations of the planets' gravitational fields. The gravitational field of a perfectly rigid body is constant. Planets aren't perfectly rigid. They instead are subject to tides. These solid body tides result in small time variations in a planet's gravitational field.

The variations in a planet's gravitational field provide a means for inferring characteristics of the planet. In particular, both Venus' and Mars' $k_2$ tidal Love number are consistent with a planet with a partially molten core but inconsistent with a planet with a solid core. The cores of Venus and Mars most likely look a lot like ours: a molten outer core, possibly surrounding a solid inner core. We'll need to place seismometers all over the surface of those planets to determine if they have a solid inner core.

$\endgroup$

Not the answer you're looking for? Browse other questions tagged or ask your own question.