NASA’s Curiosity rover is using a new experiment to better understand the history of the Martian atmosphere by analyzing xenon.
While NASA’s Curiosity rover concluded its detailed examination of the rock layers of the “Pahrump Hills” in Gale Crater on Mars this winter, some members of the rover team were busy analyzing the Martian atmosphere for xenon, a heavy noble gas.
The Five Most Abundant Gases in the Martian Atmosphere
Curiosity’s Sample Analysis at Mars (SAM) experiment analyzed xenon in the planet’s atmosphere. Since noble gases are chemically inert and do not react with other substances in the air or on the ground, they are excellent tracers of the history of the atmosphere. Xenon is present in the Martian atmosphere at a challengingly low quantity and can be directly measured only with on-site experiments such as SAM.
“Xenon is a fundamental measurement to make on a planet such as Mars or Venus, since it provides essential information to understand the early history of these planets and why they turned out so differently from Earth,” said Melissa Trainer, one of the scientists analyzing the SAM data.
A planetary atmosphere is made up of different gases, which are in turn made up of variants of the same chemical element called isotopes. When a planet loses its atmosphere, that process can affect the ratios of remaining isotopes.
Measuring xenon tells us more about the history of the loss of the Martian atmosphere. The special characteristics of xenon – it exists naturally in nine different isotopes, ranging in atomic mass from 124 (with 70 neutrons per atom) to 136 (with 82 neutrons per atom) – allows us to learn more about the process by which the layers of atmosphere were stripped off of Mars than using measurements of other gases.
A process removing gas from the top of the atmosphere removes lighter isotopes more readily than heavier ones leaving a ratio higher in heavier isotopes than it was originally.
NASA’s Curiosity Mars rover can be seen at the “Pahrump Hills” area of Gale Crater
The SAM measurement of the ratios of the nine xenon isotopes traces a very early period in the history of Mars when a vigorous atmospheric escape process was pulling away even the heavy xenon gas. The lighter isotopes were escaping just a bit faster than the heavy isotopes.
Those escapes affected the ratio of isotopes in the atmosphere left behind, and the ratios today are a signature retained in the atmosphere for billions of years. This signature was first inferred several decades ago from isotope measurements on small amounts of Martian atmospheric gas trapped in rocks from Mars that made their way to Earth as meteorites.
“We are seeing a remarkably close match of the in-situ data to that from bits of atmosphere captured in some of the Martian meteorites,” said SAM Deputy Principal Investigator Pan Conrad.
SAM previously measured the ratio of two isotopes of a different noble gas, argon. The results pointed to continuous loss over time of much of the original atmosphere of Mars.
The xenon experiment required months of careful testing at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, using a close copy of the SAM instrument enclosed in a chamber that simulates the Mars environment. This testing was led by Goddard’s Charles Malespin, who developed and optimized the sequence of instructions for SAM to carry out on Mars.
“I’m gratified that we were able to successfully execute this run on Mars and demonstrate this new capability for Curiosity,” said Malespin.
NASA’s Mars Science Laboratory Project is using Curiosity to determine if life was possible on Mars and study major changes in Martian environmental conditions. NASA studies Mars to learn more about our own planet, and in preparation for future human missions to Mars. NASA’s Jet Propulsion Laboratory in Pasadena, California, a division of Caltech, manages the project for NASA’s Science Mission Directorate in Washington.
Giraffe (Giraffa Camelopardalis) with an average height of around 5 m (16-18 ft.) is one of the tallest mammals living on planet Earth. It has over 6 feet long legs which make it taller than most human beings….
Giraffe’s long neck allows it to eat leaves located at much higher level than other animals can reach. A long tongue helps them pull leaves from the trees and eat them. A full-grown giraffe usually consumes over 45 kg of leaves and twigs a day.
The male giraffe is taller and heavier than the female.
Giraffes sleep less than two hours a day with their feet tucked under them and their head resting on their hindquarters. Female giraffes usually become pregnant after they are 5 years old. The pregnancy period generally lasts 15 months and newborns are about 6 ft. tall and weigh 70 kg
The life expectancy of Giraffes is 25 years
Giraffes are classified by IUCN’s Red List as vulnerable to extinction. The number of giraffes has plummeted 40% since 1985. Some subspecies are in even more dire situation with their population declining by nearly 80%.
Has excellent eyesight which allows it to see predators like lions and hyenas from far away
Can clean its ears with its 21 inch long tongue
Can run faster than 56 km/ph over short distances, or cruise at 16 km/ph over longer distances
Has to awkwardly spread its front legs or kneel to reach the ground to drink water
Needs to drink only once in few days. Most of this water comes from the plants they eat
Can spend most of their lives standing up- even sleep and give birth
A new born calf can stand up and walk after about an hour and eat vegetation within a week
Have distinct spots on the body like fingerprints. No two giraffes have the same spots
Male and female giraffes have two distinct, hair-covered horns called ossicones. Male giraffes use their horns to fight with other males
Needs just a short 5-30 minute sleep in 24-hours. Each short nap may last only 1-2 minute
Produce low pitched sounds which are beyond the range of human hearing range