A lot of exciting space science news coming in this weekend! Lets start with this project brief from Johns Hopkins University.
The proposal is to use a series of orbiting probes and a mothership to measure the gravity field of an asteroid or comet, and use this information to model the internal structure. Modelling the interior of small planetary bodies is something that we haven’t achieved yet as a species, simply because most of our exploration tools focus on large scale and surface features. We haven’t been able to put a drill hole into the centre of an asteroid yet!
Scientists are turning to remote sensing techniques like gravity, ground penetrating radar and radio tomography (think penetrating an asteroid with lightwaves of different frequencies and measuring the signal returning signal bouncing off different internal structures) to cheaply gather data on an asteroid’s interior.
In the above proposal the mothership will precisely monitor the position of the orbiters as they rotate the asteroid. Even a small change in orbit will reveal changes in density which can be caused by heavier or lighter material and empty spaces within. The combined data will be used to build a picture of the asteroid’s interior. This technique is already shown to be feasible through a series of simulations.
The benefits of such a project include the mothership being able to perform other experiments simultaneously, even leaving room to send a lander to the surface.
My only concern is in accurately tracking the position of the orbiters with respect to the asteroids surface. On Earth we need 4 GPS satellites to provide accurate location coordinates.
In other news, an incredible new photo reveals signs of geological features on Pluto, making a geophysicist like myself giddy with excitement. Even with a resolution of 27 kilometres, breathtaking new features can already be made out.
I think my reaction can be neatly summarised by this photo of science team members.
While it is unlikely that Pluto is still geologically active due to its small size, it seems apparent that it underwent a series of events leaving clues on its surface to its past.
As New Horizons principal investigator Alan Stern said, “After nine and a half years in flight, Pluto is well worth the wait.”
Different materials reflect various wavelengths of light in different proportions. As a result, each material has its own characteristic spectral signature.
Even with the most advanced telescopes, the light from distant planets beyond our solar system constitute a single pixel. This makes it hard to look for life, as the light signature from a planet gives us only the average of the near side of the planet.
Researchers from the University of Washington and the Virtual Planetary Laboratory published a paper in May in Astrobiology. They have found that if an organism with nonphotosynthetic pigments (which use light for things other than energy) cover enough of a planet’s surface, their influence on the spectral signature could be strong enough to be detected by a new generation of telescopes currently in development.
This possibility has been overlooked in previous searches for life, and while there are some difficulties with this method, it certainly broadens our ability to detect life at great distances.
A link to the original paper can be found here.
Until next time.