Create an account
What makes the view of Mars in the summer of 2003 so spectacular?
Mars was both at perihelion and opposition, creating the perfect viewing conditions from Earth.
Why does Mars appear fainter than Venus, as seen from Earth?
because it is smaller, farther away and less reflective
What causes the changing dark and light features visible on the Martian surface from Earth?
highly cratered and eroded areas that are frequently covered and uncovered by dust
Why is the southern hemisphere of Mars believed to be older than the northern?
The southern hemisphere is more heavily cratered.
If water caused the huge outflow channels on Mars, what was the most likely process that formed them?
catastrophic but rare flooding
Evidence of liquid water in Mars' distant past suggests that it had a substantial atmosphere compared to what it has presently. What happened to its water vapor?
The atmosphere has frozen out into the polar ice caps and permafrost as Mars has cooled.
One piece of evidence against the possibility of water on Mars is
the few carbonate rock layers that would have formed on the bottoms of oceans.
Mars' magnetic field is so weak because
it core may no longer be molten and its core contains less iron than our own.
Please allow access to your computer’s microphone to use Voice Recording.
Having trouble? Click here for help.
We can’t access your microphone!
Click the icon above to update your browser permissions and try again
Reload the page to try again!Reload
Press Cmd-0 to reset your zoom
Press Ctrl-0 to reset your zoom
It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.
Please upgrade Flash or install Chrome
to use Voice Recording.
For more help, see our troubleshooting page.
Your microphone is muted
For help fixing this issue, see this FAQ.
Star this term
You can study starred terms together