A magnetic field is caused by the internal motion of molten rock in the outer layer of a planet's core.
Mars is smaller than the Earth, so it's core has cooled down to the point where the magnetic field has all but shut down.
Mars has a weak magnetic field compared to Earth. While Earth's magnetic field is created by a liquid iron outer core, Mars' magnetic field is generated by smaller pockets of magnetized rock in its crust. The overall magnetic field strength on Mars is about 1% of Earth's.
A strong magnetic field has a higher magnetic flux density than a weak magnetic field. This means that a strong magnetic field exerts a greater force on nearby magnetic materials compared to a weak magnetic field. Additionally, strong magnetic fields are more effective for magnetizing materials or creating magnetic induction.
Mercury is the planet that has craters, cliffs, and a weak magnetic field. Its surface is heavily cratered, and there are large cliffs called scarps. Mercury's magnetic field is about 1% as strong as Earth's magnetic field.
The dynamo. For terrestrial planets, the dynamo is a molten core of nickel-iron. Mercury and Earth have fairly strong dynamos and therefore fairly strong magnetic fields. Venus and Mars do not, and have only weak magnetic fields.
We are already on a planet with a magnetic field and yes magnetic fields are what protect the planet from various dangers. Not to mention nearly every planet we have seen has a magnetic field (save venus). It is believed that the magnetic fields of planets save them from solar winds which would otherwise slowly strip the atmospheres of planets by taking out chunks of atoms every time they hit. Mars has an extremely weak (or none according to many scientists) magnetic field and as such the solar winds bash into it and scoop out ions from the planet. Overall conclusion: Yes, you want to visit a planet with a strong magnetic field, it's basically more protection (in theory at least).
Mars has a weak magnetic field compared to Earth. While Earth's magnetic field is created by a liquid iron outer core, Mars' magnetic field is generated by smaller pockets of magnetized rock in its crust. The overall magnetic field strength on Mars is about 1% of Earth's.
Mars has a very weak magnetic field compared to Earth. It is thought to be a remnant from when the planet had a more active core. This weak magnetic field is not strong enough to provide the level of protection from solar radiation that Earth's magnetic field offers.
Auroras are interactions of the planet's magnetic field with the solar wind, exciting particles in the upper atmosphere. Mars' atmosphere is thin and its field weak, so such interactions as there may be would not be visible.
A strong magnetic field has a higher magnetic flux density than a weak magnetic field. This means that a strong magnetic field exerts a greater force on nearby magnetic materials compared to a weak magnetic field. Additionally, strong magnetic fields are more effective for magnetizing materials or creating magnetic induction.
Mercury fits this description, as it has craters, cliffs (known as scarps), and a weak magnetic field. Mercury's magnetic field is only about 1% as strong as Earth's magnetic field.
The moon does not have a dipolar magnetic field and its external magnetic field is quite weak when compared to that of the Earth.
Mercury is the planet that has craters, cliffs, and a weak magnetic field. Its surface is heavily cratered, and there are large cliffs called scarps. Mercury's magnetic field is about 1% as strong as Earth's magnetic field.
Mars no longer has a magnetic field. Look at earth for a moment. The earth's magnetic field is generally thought to be the product of dynamo action associated with motion (currents) in the molten fluid core of the earth. Other planets that have magnetic fields are, in general, thought to have this same or a similar source for their fields. Mars no longer has a molten core. Our studies have revealed that there are parts of the crust of Mars that have been magnetized. We see that these areas have a residual magnetic field that has been left as an "impression" of the original magnetic field of the red planet. And that field has changed polarity at different times over the period when Mars still actually had a natural magnetic field and it magnetized portions of the crust. A link to the Wikipedia article on Mars is provided.
No, lead is not magnetic. Lead is a diamagnetic material, meaning it creates a weak magnetic field in opposition to an externally applied magnetic field.
Neptune, Uranus, Saturn, Jupiter, and Earth all have magnetic fields. Mercury has a very weak magnetic field.
The dynamo. For terrestrial planets, the dynamo is a molten core of nickel-iron. Mercury and Earth have fairly strong dynamos and therefore fairly strong magnetic fields. Venus and Mars do not, and have only weak magnetic fields.
Phobos had no magnetic field neither in the past nor present. First, Phobos is a solid satellite and thus no molten core and can't generate magnetic field. Second, even in the molten state it's size is too small that such metallic core would effectively formed and cause electrodynamics effect creating magnetic field.