Today, some students asked questions about auroras to NASA scientist Jim Spann during a NASA chat. Here are a few of the questions and answers shared by the chat moderator:
jim_spann: The colors of the aurora range from deep reds to greens and occasionally blues. The colors depend on which atmospheric constituent was excited. The red ones are dominated by oxygen and the green ones by molecular nitrogen.
jim_spann: This is a great question. There are two points I would make with regard to the impact of auroras on technology. I want to introduce the concept of space weather. The aurora is our most obvious manifestation of space weather. Space weather is the dynamic aspect of the plasma that occupies space above our atmosphere. The aurora results from space weather that is driven by the variability of our star, called the Sun. Space weather can cause spacecraft to malfunction or become disabled. This impacts a lot of technology, in particular communications. So that is the first point I would make about the aurora or space weather impacting technology on Earth. The second point is that when there are large space weather events called magnetic storms, the aurora kicks up and becomes very active and very bright. Another consequence of a magnetic storm is that the currents that are created by the charged particles that cause the aurora induce other currents along our power lines and pipelines. These currents in the powerlines can cause failures to power transformers on the power grid. An example occurred in 1986 in Quebec that took out the power to millions of people in the Northeast. If we were to have a huge magnetic storm, much larger than we've experienced recently, significant damage to society's infrastructure could occur.
Are there auroras on Mars?
jim_spann: There are two things that are required for auroras. One is a magnetic field and the other is an atmosphere. Mars has an atmosphere, but a very, very weak, disorganized magnetic field. Therefore, you would not see an aurora at Mars. But you would see the atmosphere glow if you had good enough sensitivity. In fact, a NASA mission called MAVEN is arriving at Mars and will observe the Mars air glow. *
(*It should be noted that Jim Spann brought up auroras have been captured by the Hubble telescope and Cassini mission elsewhere in the Solar System! However, a planet without an atmosphere will not have auroras.)
What colors can auroras be? What causes the color change?
jim_spann: The colors of the aurora range from deep reds to greens and occasionally blues. The colors depend on which atmospheric constituent was excited. The red ones are dominated by oxygen and the green ones by molecular nitrogen.
How can auroras impact technology here on Earth? Do they have any impact on living things?
jim_spann: This is a great question. There are two points I would make with regard to the impact of auroras on technology. I want to introduce the concept of space weather. The aurora is our most obvious manifestation of space weather. Space weather is the dynamic aspect of the plasma that occupies space above our atmosphere. The aurora results from space weather that is driven by the variability of our star, called the Sun. Space weather can cause spacecraft to malfunction or become disabled. This impacts a lot of technology, in particular communications. So that is the first point I would make about the aurora or space weather impacting technology on Earth. The second point is that when there are large space weather events called magnetic storms, the aurora kicks up and becomes very active and very bright. Another consequence of a magnetic storm is that the currents that are created by the charged particles that cause the aurora induce other currents along our power lines and pipelines. These currents in the powerlines can cause failures to power transformers on the power grid. An example occurred in 1986 in Quebec that took out the power to millions of people in the Northeast. If we were to have a huge magnetic storm, much larger than we've experienced recently, significant damage to society's infrastructure could occur.
Are there auroras on Mars?
jim_spann: There are two things that are required for auroras. One is a magnetic field and the other is an atmosphere. Mars has an atmosphere, but a very, very weak, disorganized magnetic field. Therefore, you would not see an aurora at Mars. But you would see the atmosphere glow if you had good enough sensitivity. In fact, a NASA mission called MAVEN is arriving at Mars and will observe the Mars air glow. *
(*It should be noted that Jim Spann brought up auroras have been captured by the Hubble telescope and Cassini mission elsewhere in the Solar System! However, a planet without an atmosphere will not have auroras.)
