Date: February 25, 2011

Title: Exploring the Solar System: Mercury

Podcaster: Thomas Hofstätter

Organization: The Hidden Space Project: http://hidden-space.at.tf

Description: This is the first podcast of several about the exploration of our solar system. Starting at the inner edge of the planetary system, Mercury is described in this article closer. Interesting points and curious facts are pointed out. There’s also a short description of the missions observing the planet including it’s magnetic field.

If you have any questions, comments or suggestions to the podcast, feel free to write me an email to hidden-space (at) gmx (dot) at or visit me at my website at www.hidden-space.at.tf!

Bio: Born in 1993 near Vienna, Austria, Europe. Upper High School with focus on Computer Science.Interested in extreme small and extreme big, devious and uninvestigated things. My main aim is to bring astronomy to public and to establish secular interest in astronomy, physics and mathematics. Host of :: The Hidden Space Project :: at http://hidden-space.at.tf.

Today’s sponsor: This episode of “365 Days of Astronomy” is sponsored by Greg Dorais, and is dedicated to the Chabot Space And Science Center in Oakland California, home of Bill Nye’s Climate Lab, Space Explorers Summer Camp, and so much more. At Chabot Space And Science Center, the universe is yours to experience. Set amid 13 trail-laced acres of East Bay parkland, with glorious views of San Francisco Bay and the Oakland foothills, Chabot is a hands-on celebration of sights, sounds, and sensations. Find out more about the Chabot Space And Science Center at www.chabotspace.org.

Transcript:

Hello and welcome to this episode of 365 Days of Astronomy. My name is Thomas Hofstätter and I am the hoster of :: The Hidden Space Project :: at www.hidden-space.at.tf.

[Leon:] And I’m Leon Dombroski from the state of Connecticut in the United States.

Starting the tour through our solar system visiting all planets and some other celestial objects, the first to be observed closely is Mercury. Over a long period of time, it wasn’t known exactly whether there were other planets orbiting the sun closer than Mercury. Some scientists thought so because their observations didn’t fit to the then known theory of gravity by Isaac Newton.

[Leon:] Newton’s law says that all masses are attracting each other. This pull is declining with the square of the radius and is then multiplied by a constant. According to the General Theory of Relativity by Albert Einstein, this is not the fact any more. Einstein discovered that space and time aren’t constant but can be bent. The both hence form something called space-time, which is bent by the influence of masses, like our sun.

The influence of the sun first on space-time was proofed 1919 by Sir Arthur Eddington. A curious fact is that the uncertainly of the observations were equal to the effect itself. Hence, it was just luck that Eddington proofed General Relativity and didn’t disproof it.

[Leon:] To come back to Mercury: According to older observations, there should have been another object between Mercury and the sun. In fact, the calculations weren’t exact enough. Considering General Relativity, it’s impossible for another celestial object to orbit closer to the sun than Mercury.

Mercury is the smallest planet of the solar system. Else, the orbit wouldn’t be possible. Another fact is based on the origin of the solar system when material formed in a circumstellar disc. Moreover, Mercury has the most eccentric orbit but the smallest axial tilt. Due to the high differences between aphelion and perihelion, the surface temperature differs from 380C and 530C. But there are also areas that never face the sun. These areas have temperatures of -60C to -70C.

[Leon:] Because Mercury has no bigger atmosphere, the differences of temperature don’t equate. Mercury is too small to hold an atmosphere. The more, scientists were surprised when they actually found one. They recognized that particles and radiation of the sun cause gas of the surface material to form a thin atmosphere, which is a few centimeters thick.

These observations were made with the two probes that actually observed Mercury: Mariner 10 and MESSENGER. Mariner 10 was launched in 1973 and had three flybys in 1974. MESSENGER was launched in 2004 and also had three flybys, as yet. This year, MESSENGER is to inject into Mercury’s orbit and will deliver the most accurate map of Mercury for the next decades.

[Leon:] The two probes also observed the magnetic field of Mercury. The strange thing they found out was, that the magnetic field is not consistent. This fact is caused by the solar radiation that “presses” the magnetic field away. The effect is also known at the earth, but not as strong as on Mercury.

All in all, Mercury is a hot place where life is thought to be impossible. The only possible areas for life are located at the edge of some craters where the temperatures are humid due to the small amount of light and heat of the sun in the shadow…

[Leon:] Perhaps, MESSENGER is to tell us more about this! Although MESSENGER hasn’t even swung into Mercury’s orbit, the next mission is in preparation. It’s name is BepiColumbo and it’s a cooperation between the European Space Agency and the Japan Aerospace Exploration Agency. BepiColumbo is scheduled for launch in 2014.

That’s it for today. I hope, you enjoyed it. If you have any questions, comments or suggestions, write me an email to hidden-space (at) gmx (dot) at or visit me at my website at www.hidden-space.at.tf.

Thanks for listening and clear-skies!
[Leon:] Good bye for now!

New stories are to come soon!

End of podcast:

365 Days of Astronomy
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