The November Skies
Coming out of the solar glare, Mercury begins its best morning apparition of the year in the second week of November. Look for it low in the east-southeast before sunrise. During the last week of the month, Mercury drops lower in the sky each morning.
Venus appears as the “Evening Star” this month, low in the southwest at dusk.
Mars is high in the southeast at dawn. NASA plans to launch a newly designed and highly advanced Mars Rover in 2020.
Bright Jupiter rises in the east at about 9:30 p.m. early in November. Its four large Galilean moons are visible in steady binoculars.
During the second half of November, look for Saturn low in the east-southeast predawn sky. Mercury and Saturn have a close conjunction on the morning of Nov. 26.
Daylight Saving Time ends at 2 a.m. on Nov. 3 for most of the country.
The Leonid Meteor Shower peaks on the night of Nov. 17-18. The best time to watch for these meteors will be between midnight and dawn on this night. Usually, an average of about 40 meteors per hour can be seen from a dark observing site. However, this year, a full moon will outshine all but the brightest ones.
THE PROMISE OF GRAPHENE
“We live in a society exquisitely dependent on science and technology, in which hardly anyone knows anything about science and technology.”
– Carl Sagan, 1934-1996
What is the world’s thinnest yet strongest material? It’s a material that conducts electricity as efficiently as copper and is presently the best known conductor of heat. Although it is nearly transparent, it’s so dense that even the smallest atom (helium) cannot pass through it. It is photosensitive to broad spectrum light, from the visible to mid-infrared, and is many hundreds of times more sensitive to light than the imaging sensors in today’s cameras. Most recently, scientists discovered that this material can be made magnetic and this magnetism can be switched on and off at the touch of a button. This novel and very wondrous material is called graphene and its unique combination of properties will undoubtedly lead to incredible technology advances in several fields. If you haven’t heard about it yet, you surely will in the very near future.
Graphene is only one-atom thick, which is a million times smaller than a human hair. It is made up of pure carbon atoms that are arranged in a honeycomb structure. It’s actually the same material as graphite, which is the “lead” found in the center of pencils, except that graphene consists of just one single layer of carbon atoms.
One of the greatest possible uses of graphene, a use that could dramatically change the world, will be in the attempt to use it to desalinate seawater. The reverse osmosis process presently in use, using semipermeable membranes, began to be feasible in the 1950s but has many disadvantages. A graphene-based membrane would allow scientists to create optimum size holes to allow water molecules to pass through but would block the sodium and chloride ions. Graphene desalination plants would be much more efficient and cheaper to run than the traditional ones. Since about 98 percent of all water on Earth is salt water, graphene could turn out to be a lifesaver for future generations.
At the present time, scientists are “growing” sheets of graphene somewhat larger than television screens. This is done in a process called chemical vapor deposition in which single atomic layers are grown on various substrates inside a high-temperature furnace. Even when stacked in multiple layers, the resulting material is thousands of times lighter and thinner than tissue paper. When used to convert sunlight to electricity in future solar cells, stacking multiple layers will significantly boost the efficiency.
For many years, the science fiction idea of a space elevator has been kicked around by astrophysicists. This elevator would be connected to an orbiting satellite by a very long tether made of carbon nanotubes and sheets of graphene, the only materials light enough and strong enough to accomplish such a mission. Once constructed, personnel and supplies could be shuttled back and forth between Earth and the satellite in an elevator attached to the tether. The idea sounds “way out there” now but who knows what the future will bring.
Editor’s note: This monthly guide to the stars is from the Marshall Martz Memorial Astronomical Association and the Post -Journal. For further information, contact the M.M.M.A.A. at www.martzobservatory.org.