InSight Mission Blasts Off To Mars / Chance For Weekend Auroras

This illustration shows the InSight lander with its seismometer (left) and temperature probe in place. NASA

We’re headed back to Mars! NASA’s Mars InSight mission lifted off at 6:05 a.m. (Central Time) this morning from the West Coast en route to the Red Planet. After a 6½ month journey, it will arrive and set up camp on Nov. 26. The landing site is Elysium Planitia, a broad, smooth plain just north of Mars’ equator. The probe needs a flat, relatively rock-free place to land and set up its instruments.

InSight is an acronym for Interior Exploration using Seismic Investigations, Geodesy and Heat Transport. Unlike other missions to explore and map the Martian surface or atmosphere, the InSight lander will study the planet’s guts using a seismometer to detect marsquakes and a temperature / heat probe that will penetrate 16 feet (5 meters) into the ground to measure the planet’s interior temperature.


Overview of the Mars InSight mission

A third experiment uses radio waves sent from Earth to the lander to determine its exact location. Mars orbits the sun in just under two years. During that time, the sun pushes and pulls on the planet, causing it to wobble slightly. It also changes the frequency of the radio signal reflected back to Earth from the lander. Measuring those changes yields not only the size of Mars’ iron-rich core but will help to determine whether it’s liquid, and what other elements, besides iron, may be present.

By getting right to the core of things (so to speak), scientists hope to learn more about how Mars formed but also other rocky planets like the Earth, Venus, Mercury and even the moon. We might also come to better understand why Mars lost its planetary-wide magnetic field, the planet’s main defense against having its atmosphere stripped away. Mars is in part so cold and desert-like today because of its skimpy atmosphere, about 100 times thinner than Earth’s.

Watch for the Eta Aquarids in the eastern sky over the next couple nights between about 3 a.m. and dawn. The annual shower litters Earth’s upper atmosphere with small fragments of Halley’s Comet. It radiates from the direction of the star Eta Aquarii low in the eastern sky.  Bob King, source: Stellarium

Mars is currently visible in the morning sky and shines brighter than Vega and Arcturus. You’ll have no difficulty finding it because the waning moon will sit just above the planet in conjunction tomorrow before dawn. I prepared a map but can’t upload images to the blog at the moment; please click here to see it. If you are out in the early morning and see a few meteors streaming from the east, they’re probably pieces of Halley’s Comet. The Eta Aquarid meteor shower peaks this weekend. Although greatly compromised by the moon, you might see a few.

A coronal hole on the sun streaming particles toward Earth will likely spark a minor G1 geomagnetic storm both tonight and Sunday night. The space weather experts forecast possible auroras late tonight (after midnight Central Time) and between 10 p.m. and 1 a.m. Sunday. Watch for a low, bright arc low in the northern sky as your first clue the aurora is active. We all know that the northern lights can sometimes turn up earlier or later than expected, so give a look anytime you’re outside this weekend.

2 Responses

  1. kevan Hubbard

    What i fail to understand is why Venus has such a thick atmosphere yet no magnetic field,even Mars has a stronger if residual magnetic field than Venus. Venus closer to the sun should have lost its atmosphere? I’ve read 3 theories;1/the solar wind induces a pseudo protective magnetic field as it interacts with the atmosphere, 2/volcanic activity keeps it topped up,3/the theory about the solar wind stripping atmospheres is wrong.

  2. astrobob

    To Kevan — The likely reason Venus has no magnetic field is because it rotates incredibly slowly — its day lasts longer than its year, 243 days vs. 225 days. You’ve got to rotate the liquid iron its core fast enough to create the currents necessary for a magnetic field.

    Venus does not lose its atmosphere like Mars because it is a much more massive planet and can hold onto it. It’s much easier to pry molecules from Mars because it’s gravitational pull is too weak to hold onto them.

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