Mars
Page contents
1 Is Mars habitable?
2a Search for Life
2b Would We Know Alien Life If We Saw It?
2c How long will it take to reach Mars using existing methods?
2d How much does it cost to go to space?
Nothing vital to life from this point.
Saves opening another page.
Pages for those with serious interest
3 Mars goes backwards!
4 Draw a dot on a sky map each night
5 Methane
6 Curiosity Rover on Mars Spotted ..in Awesome NASA Photo
7 More on the Search for Life
For everyone: foot of page.
1 Is Mars habitable?
- With the right technologies, yes.
- What do we mean when we say an environment is “habitable”?
- When referring to exoplanets, the term “habitability” is usually equated to whether or not liquid water can exist on the planet’s surface.
- But that doesn’t always answer the question of whether humans can inhabit a given environment.
- After all, Earth’s South Pole doesn’t have liquid water on the surface. ... Yet resourceful humans have been inhabiting both locations for decades.
- . . . Mars is on the outer boundary of our solar system’s habitable zone, and we know what looks like briny, liquid water can exist on the surface for short periods of time.
- But does that really make Mars habitable?
- From a practical standpoint, the answer depends on what technologies we bring there to create our own artificial habitable zones on the surface.
- Long-term habitation on Mars will require us to master the conversion of raw Martian materials into resources we can use to survive.
- Fortunately, Mars has a wealth of these materials, making it arguably the most human-habitable place in the solar system, other than the Earth itself.
- ........
- H2O from the atmosphere and polar iceMars is a dry planet compared to the Earth, but compared to other celestial bodies like the moon and asteroids, its water budget is quite generous.
- Mars has a polar cap composed of a mixture of water-ice and CO2 dry ice, and even at non-polar latitudes, water-ice is known to exist a few meters under the surface regolith.
- This water can be purified and consumed, or electrolyzed to produce O2 and hydrogen, which can be further combined with atmospheric CO2 to produce a range of useful plastics.
2a Search for Life
- With an atmospheric pressure less than 1 percent of Earth’s and
- temperatures typically well below freezing, the surface conditions
- of Mars cannot currently maintain even puddles of liquid water.
- Was there ever life on Mars? Over the past 40 years, NASA has sent a number of
- spacecraft to orbit and land on Mars to better address such questions.
- One of the best reasons to study other planets in detail is to gain a better understanding of the physical processes that have shaped the Earth.
2b Would We Know Alien Life If We Saw It?
- At this moment, seven robotic spacecraft are roving or orbiting Mars, taking photos, gathering data, and generally doing the bidding of scientists back on Earth.
- After 15 years of this continuous robotic presence, we know the Red Planet better than any world besides our own.
- And planetary scientists have an answer, finally, to one of their oldest and most fundamental questions: Could Mars support life?
- The answer is yes: certainly in the past, and very possibly today.
- In 2013, less than a year after Curiosity touched down in the ancient lakebed Gale Crater, John Grotzinger, the project’s principal investigator, announced with confidence: “We have found a habitable environment,” one where substantial amounts of surface water existed billions of years ago.
- What’s more, the Curiosity science team is convinced that the lakes and streams lasted for long periods, perhaps millions of years.
- Another announcement, just as momentous, followed last September 2015: Water still flows on Mars today—at or very near the surface.
- For more than a decade, NASA’s strategy in exploring Mars has been to “follow the water”; the agency reasons that wherever there’s water, we might find life.
- Now, having made the case for water, space agencies are preparing to launch Mars missions whose primary purpose is to search for evidence of biology.
- And, unlike earlier searches, these missions have a real chance for success.
2c How long will it take to reach Mars using existing methods?
- The trip takes around seven months; a bit longer than astronauts currently stay on the International Space Station.
- The precise duration of each journey depends on when it is taken.
- Because both Mars and Earth's orbits are not perfectly circular, the time it takes to travel between them varies from six to eight months.
source via Seven months.
2d How much does it cost to go to space?
Depending on where you're going, a ticket could set you back anywhere from
$250,000 to tens of millions of dollars. If you're looking simply to cross the 62-mile-
high Karman line that marks the boundary between the upper atmosphere and outer
space, Virgin Galactic says it will take you there for $250,000.
15 Oct 2018 source
Nothing vital to life from this point.
3 Mars goes backwards! ?
- It Happens Every Two Years
- The two planets are like racing cars on an oval track.
- Earth has the inside lane and moves faster than Mars -- so much faster, in fact, that it makes two laps around the course in about as much time as it takes Mars to go around once.
- About every 26 months, Earth comes up from behind and overtakes Mars.
- While we're passing by the red planet this year, it will look to us as though Mars is moving up and down.
- Then, as we move farther along our curved orbit and see the planet from a different angle, the illusion will disappear and we will once again see Mars move in a straight line.
- This apparent erratic movement is called "retrograde motion." The illusion also happens with Jupiter and the other planets that orbit farther from the sun.
Just to make things a little more odd, the orbits that Earth and Mars follow don't quite lie in the same plane.
It's as if the two planets were on separate tracks that are .. tilted with respect to each other. This causes another strange illusion.
Can you work out which orbit is which?
M V E M J S U N
Boarding passes obtainable from here!
4 Draw a dot on a sky map each night
- If you were to look up in the eastern sky at the same time each night and note where Mars appears to be compared to the constellations of stars, you would find the planet a little farther east with each viewing.
- That is, Mars appears to move from west to east from one night to the next.
- Every two years or so, there are a couple of months when Mars' position from night to night seems to change direction and move east to west.
- This strange behavior was very puzzling to early skywatchers.
- Did the planet really stop, back up, change its mind, and then continue to move forward? Did it have some weird, mystical meaning?
- Suppose you were to draw a dot on a sky map each night to show where Mars appears as it moves forward, goes through retrograde, and then resumes its forward motion.
- Connect the dots, and you'll draw either a loop or an open zigzag. The pattern depends on where Earth and Mars happen to be in their tilted racetrack orbits.
.14
Today we know what's going on. It's an illusion, caused by the ways that Earth and Mars orbit the sun.
5 Methane
.1
Unique chance to confirm methane .. and perhaps
life on Mars Planetary scientists are interested in
methane on Mars because it could be a sign of life.
.2
Although it can be produced by geological sources,
on Earth the vast majority of the gas is pumped out by
microbes and other living things. On Earth
,3
We have spotted tantalising glimpses of methane
burps on Mars a few times over the years, but it
has been difficult to confirm the detections with
other instruments.
.4
Some sort of destruction mechanism might quickly
remove methane from the lower atmosphere,
but the uncertainty has led to scepticism about past
methane sightings.
.5
This time could be different. Giuranna says that
Mars Express just happened to have its spectrometer
trained on Gale Crater for an extended period, a
technique known as “spot tracking”, around 20 hours
before the rover made its detection on the ground,
as well as a day later.
.6
“We typically have a couple of spot-tracking events
per month, so we were lucky here,” he says.
.7
Another satellite called the Trace Gas Orbiter, which
boasts two instruments capable of detecting methane,
also has data from the same area on the same day.
6 Curiosity Rover on Mars Spotted from Space in Awesome
NASA Photo here
7 More on the Search for Life
- With an atmospheric pressure less than 1 percent of Earth’s and
- temperatures typically well below freezing, the surface conditions
- of Mars cannot currently maintain even puddles of liquid water.
- Was there ever life on Mars? Over the past 40 years, NASA has sent a number of
- spacecraft to orbit and land on Mars to better address such questions.
- One of the best reasons to study other planets in detail is to gain a better understanding of the physical processes that have shaped the Earth.
- The radius of Mars is about half that of Earth.
- The total Mars surface area is about equal to the land surface area of Earth.
- The mass of Mars is only about 10 percent that of Earth.
- A 150-pound person on Earth weighs 55 pounds on Mars.
- Mars is about 1.5 times farther away from the Sun than Earth, and
- it receives 2.3 times less sunlight than the Earth.
- Mars exhibits seasons like Earth; its rotation axis has a similar tilt.
- A Martian day is 24.67 hours, and a Martian year is 1.88 Earth years.
- Seasons are most noticeable at the polar caps on Mars.
You could sit down to a long video about Mars here.
