Podcaster: Dr. Al Grauer
Title: Travelers in the Night Eps. 807 & 808: Moon Orbit Crossers & Global Auroras on Mars
Organization: Travelers in The Night
Link : Travelers in the Night ; @Nmcanopus
Description: Today’s two stories:
- During a recent 60 day period of time 23 space rocks came closer to Earth than our Moon.
- When the Earth enters a stream of high speed protons and other charged particles in the solar wind or our home planet is impacted by a solar coronal mass ejection the Earth’s strong magnetic field acts a a shield. Mars on the other hand lacks an Earth-like magnetic field and thus has little protection from solar storms.
Bio: Dr. Al Grauer is currently an observing member of the Catalina Sky Survey Team at the University of Arizona. This group has discovered nearly half of the Earth approaching objects known to exist. He received a PhD in Physics in 1971 and has been an observational Astronomer for 43 years. He retired as a University Professor after 39 years of interacting with students. He has conducted research projects using telescopes in Arizona, Chile, Australia, Hawaii, Louisiana, and Georgia with funding from NSF and NASA.
He is noted as Co-discoverer of comet P/2010 TO20 Linear-Grauer, Discoverer of comet C/2009 U5 Grauer and has asteroid 18871 Grauer named for him.
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Transcript:
Ep. 807: Moon Orbit Crossers
During a recent 60-day period of time, 23 space rocks came closer to Earth than our Moon. These Moon-orbit crossers had diameters ranging from 6 to 175 feet, with the average being about 47 feet.
According to the Earth Impact Calculator from the Imperial College of London and Purdue University, one about the average size in this group of Moon-orbit crossers enters the Earth’s atmosphere once every 16.2 years, bursts into a cloud of fragments at 102,000 feet, creates a light show if it happens at night, and harmlessly rains pieces onto the Earth’s surface. This is an exciting event, and asteroid hunters are currently able to track some such impactors as they come toward our home planet, and have been able to predict where meteorite hunters will be able to discover pieces of these visitors from outer space. We have observed small space rocks impacting the Moon, and from all of its craters, we can estimate how many have done so in the past.
In fact, at 1114 GMT on February 23rd of 2023, Daiichi Fuji, curator of the Hirosuka City Museum in Japan, recorded a flash of light from a tiny object as it struck the Moon, using cameras set up to continuously monitor our next-door neighbor. This impact likely left a crater about 40 feet in diameter that may eventually be imaged by NASA’s Lunar Reconnaissance Orbiter, or India’s Chandrayaan-2 lunar probe. NASA has a program to look for new tiny craters, and has used the Lunar Reconnaissance Orbiter to spot a small new crater on the Moon that is the probable impact point of Russia’s Luna-25 probe.
Ep. 808: Global Auroras on Mars
. When the Earth enters a stream of high-speed protons and other charged particles in the solar wind, or our home planet is impacted by a solar coronal mass ejection, the Earth’s strong magnetic field acts as a shield and guides these charged particles to our north and south magnetic poles, creating beautiful auroral displays.
Occasionally, most often during solar maximum, a particular energetic solar burp produces worldwide auroral displays. Mars, on the other hand, lacks an Earth-like magnetic field and thus has little protection from solar storms. Recently, when solar activity was causing auroras to be visible as far south as Arizona and Alabama, NASA’s MAVEN satellite detected auroras on Mars.
MAVEN views Mars in the ultraviolet, which in NASA images is portrayed as purple. To an astronaut standing next to NASA’s Mars Curiosity rover, Martian auroras would likely have appeared to be green or maybe even blue patches or bands of light in the Martian sky. On Earth, our magnetic field protects us from harmful radiation from solar storms, whereas an astronaut standing on Mars during a recent solar storm would have received as much radiation as 100 chest x-rays and would have likely been advised to seek shelter near a Martian cliffside or lava tube. A space traveler in Mars orbit or deep space could receive a much more dangerous dose of radiation during a solar storm. All of this leads us to a more profound appreciation of our home planet where our magnetic field protects us as we can view space weather in perfect safety.
For Travelers in the Night, this is Dr. Al Grower.
End of podcast:
365 Days of Astronomy
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