Context
NASA recently detected Earth’s hidden ambipolar electric field for the first time
About Ambipolar Electric Field:
- A weak, planet-wide electric field affecting the movement of charged particles in Earth’s atmosphere, as fundamental as gravity and magnetism.
- Proposed in the 1960s.
- Mechanism:
- Generated at around 150 miles altitude.
- Interacts with charged particles (ions and electrons), preventing charge separation.Helps lift some ions high enough to escape into space.
- Bidirectional: Works in both directions—lifting ions into space and pulling electrons downward, tethering them together.
- Extends the height of the atmosphere.
- Detection: Confirmed by a NASA suborbital rocket as part of the Endurance mission, which quantified the field’s strength.
Effects on Earth’s Atmosphere
- Increased Scale Height:
- Raises the ionosphere’s “scale height” by 271%, keeping it denser at higher altitudes.
- Ionosphere: A layer in the upper atmosphere abundant with charged particles.
- Polar Wind:
- Contributes to the polar wind, driving charged particles into space.
- An ambipolar (bidirectional) outflow of thermal plasma from the high-latitude ionosphere to the magnetosphere.
- Composed primarily of hydrogen, helium, and oxygen ions, along with electrons.
- Effect on Hydrogen Ions:
- The ambipolar field exerts a force 10.6 times stronger than gravity on hydrogen ions.
- Propels them into space at supersonic speeds, enhancing atmospheric escape.
- Broader Implications:
- Provides insights into Earth’s atmospheric evolution.
- Can be applied to other planets with atmospheres, like Venus and Mars.
- Helps understand which planets could be hospitable to life.
About Endurance Mission
- NASA-funded mission
- Conducted through the Sounding Rocket Program at NASA’s Wallops Flight Facility, Virginia
- Primary Goal: Measure Earth’s global electric potential, which is believed to be very weak.
- Importance: Understanding Earth’s electric potential helps explain why Earth can support life, unlike planets like Venus.
Source:
BBC
Previous Year Question
What is ‘Greased Lightning-10 (GL-10)’, recently in the news?
[UPSC Civil Services Exam – 2016 Prelims]
(a) Electric plane tested by NASA
(b) Solar-powered two-seater aircraft designed by Japan
(c) Space observatory launched by China
(d) Reusable rocket designed by ISRO
Answer: (a)
