Skies Over Crestone: November

by Kim Malville

November 1: Daylight Savings Time ends. This month is a great one for Mars.  At the start of the month Mars will be almost as bright at Jupiter.

November 12-14: Look to the east for the crescent moon, Venus, Spica and Mercury just before sunrise.  Spica will be below Venus and Mercury will be further down.

November 17: Leonid meteor shower—best viewed before dawn.

November 19: The moon forms a triangle with Jupiter and Saturn.

November 30: Penumbral (the earth’s outer shadow) lunar eclipse. The moon will be darkened during a half hour centered around 2:43am. This is not as spectacular as a total lunar eclipse.  The next one will be May 26 of next year.

Astronomical Spectaculars of the Month

Life on Venus!

It seems that every month there is another astronomical newsworthy event. In early October there was the bombshell announcement that our hellishly hot sister planet Venus may have life hiding out high in its atmosphere. How odd, Venus is the Goddess of Beauty, when her surface is so hellish! Hot—900° F—suffocating atmosphere 93 times the pressure on earth (same as 3000 feet under the ocean!). It is wracked by volcanoes spewing carbon dioxide into an atmosphere that had already transformed Venus into the worst example of global warming. If you lived on Venus you wouldn’t ask for rain, as rain in the atmosphere consists of hot sulfuric acid.

Touchdown on Bennu by Osirus Rex photo courtesy of NASA

But, surprise of surprises, on 14 September, scientists revealed that they had found phosphine in Venus’s atmosphere, about 35 miles above the surface. Astrobiologists have flagged phosphine —a toxic compound of hydrogen and phosphorus —as a possible signature for life on other planets, and it is made by some organisms on Earth, that live without oxygen. Anaerobic life produces phosphine. But the gas should be broken down in Venus’s hot acidic atmosphere. Thus there must be some mechanism replenishing the gas, either biological or an unknown chemical process. The region of the atmosphere where phosphine was found is a place where some kinds of airborne microbes, perhaps also viruses, could survive. The amount of phosphine is very small, and its existence still needs to be fully confirmed. In any case, whatever life exists in its atmosphere is probably not as intelligent as we are on Earth.

Touching an asteroid

Bennu, Egyptian mythological bird responsible for creation
Jeff Dahl, Wikimedia Commons

Located more than 200 million miles from Earth, Bennu is an ancient asteroid, which is probably unchanged since the origin of the solar system. Some 1600 feet across, it’s a “rubble pile” consisting of rock, pebbles, and dust that are loosely held together by self-gravity and greasy surfaces. Bennu has been visited the OSIRIS-REx mission, which stands for Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer. The spacecraft reached the asteroid on December 2018 and orbited it for nearly two years, observing it in great detail, and mapped it in greater detail than our own moon.

Bennu is important not only because it a remnant of the earliest days of our solar system, but also because it is a near-earth-asteroid and may be on a collision path with the earth. There is a 1 in 2700 chance of it hitting the earth sometime between 2175 and 2199 CE. If it indeed it has Earth in its cross-hairs sometime in the future, how could we protect ourselves? It is now clear that sending a bomb to deflect that pile of rubble would be a disaster because most of its loosely bound rocks would simply rearrange themselves and continue to Earth as a huge shower of rocks. The asteroid has already been sending small messengers to us in the form of tiny particles that light up in our atmosphere every year on September 25 as a minor meteor shower.

Bennu was named in 2013 by a nine-year-old boy from North Carolina who won the Name that Asteroid! competition. Michael Puzio won by suggesting that the spacecraft’s arm and solar panels resemble the neck and wings of a heron. The name, Bennu, comes from an Egyptian mythological heron who played a role in creating the world. According to Egyptian mythology the world is periodically destroyed by floods. During the last one, a bird named Bennu flew over the watery abyss and perching on a rock that had just appeared. Bennu called out in the watery darkness asking the god Atum to create the world. Just recently, the remains of a huge heron, as tall as a human, which became extinct in 1500 BCE were recently discovered in the UAR. The image of Bennu, found in New Kingdom tomb paintings, may have been inspired by that same now-extinct bird.

On October 20 OSIRIS-REx touched Bennu with a 11-foot arm containing a hubcap-shaped collection plate at its end. At the moment of contact, which lasted just 6 seconds, the spacecraft fired off a puff of nitrogen gas to blow tiny pieces into its collection device.  The sample of rock and organic grease—perhaps amino acids-—will be stored in a capsule to be sent to earth, parachuting onto the desert of Utah on September 24, 2023.

The asteroid Bennu 
photo courtesy of NASA

Update (26 October): The goal of OSIRIS-REx was to collect up to 60 grams of the asteroid.  Now it appears that they were extraordinarily successful, gathering some 400 grams of stuff. However, some rocks jammed the lid on the collector preventing it from sealing. Some of the rubble is leaking out. They had planned to twirl the vehicle and measure the spacecraft’s inertia to determine the weight of the sample. But that would mean losing more of the sample, and the twirl has been cancelled. The OSIRIS-REx team won’t know how much has been gathered until the collector returns to Earth in a little less than three years. Such is the uncertainty that space scientists have to live with.