Free Floating Planet and November Night Skies over Tanzania

By Dr. N. T. Jiwaji

ntjiwaji@yahoo.com

The discovery, a few days ago, of a free-floating planet, has raised excitement among astronomers who expect billions of such free worlds to exist. The find, however, has frightened those waiting for the world to end this December! Though the planet is relatively close to us - 100 light years, it cannot reach us by 21^st December. It would have to travel 3 trillion kilometres every day! Such speeds would tear the planet itself apart. Our Earth is not going anywhere soon.

This artist’s impression shows the free-floating planet CFBDSIR J21494

http://www.universetoday.com/98478/new-rogue-planet-found-closest-to-our-solar-system/#more-98478

The new exoplanet, named CFBDSIR2149 would have formed by attraction by gravity of abundant hydrogen and helium gas in space. However, such a protostar is not big enough to heat up sufficiently to start nuclear fusion reactions to make it shine as a star. An example of such a protostar, also called a brown dwarf, is our own Jupiter which just failed to become a star because its mass is just lower than that needed to make it start nuclear fusion and release the energy to shine.

On November 28, the last eclipse of 2012 will occur as a penumbral lunar eclipse. It will, however, not be too obvious to our eyes since the shadow in a penumbra is a very slight. The eclipse will be in progress as the full moon rises in the east at sunset that day. However, since this is a deep penumbral eclipse it will be challenging to make out the difference once the Moon comes out of the shadow at 7:52 pm. This lunar eclipse follows a total solar eclipse that occurred at New Moon time on 13/14 November almost entirely over the southern Pacific Ocean.

The next eclipse that we can look forward to, will be a partial solar eclipse on November 3 next year, when about 60 percent of the Sun’s disk will be covered. Observers in northern Uganda and northern Kenya will be directly under the path of the eclipse, so it would be useful to plan a trip there to observe the Sun being covered by nearly 90 percent during its annular (ring) phase.

Jupiter is the planet to watch now and will shine extremely bright during the coming year. It begins to enter our early evening sky towards the end of this month. On November 23 it will be seen high above the northeast horizon at 8 pm, while the Moon will be in its first quarter phase with a half moon shape. At that time the prominent Orion constellation will also be rising in the east.

In the early morning skies, near the end of the month, Venus and Saturn make a close approach close to the eastern horizon at dawn. Venus shifts lower and lower day by day while Saturn get higher simultaneously. They will be closest on November 27 about 20 degrees above the horizon just before sunrise. After the end of November, Venus will be in line with the Sun and will remain invisible until May next year. Visit www.astronomyintanzania.or.tz for planet updates and more information

The Andromeda galaxy, the farthest galaxy (at 2 million light-years away) that we can see with our naked eyes is close to the Square of Pegasus nearer to the northern horizon, while our nearest galaxy, (at half a million light-years), the South Megallanic Cloud, lies at the opposite end of the sky in the south, between Achernar and the south point. In relatively dark skies, both galaxies appear as fuzzy patches about 4 degrees across (4 fingers held at an arm’s length).

The bright stars this month that are worth knowing by name are: Fomalhaut, Altaír, Deneb in Cygnus (the northern bird), Vega, Achenar, and last Aldebaran, which is in the constellation Taurus just rising in the east. These are all first magnitude stars. Algol in Perseus is a special star because it varies continuously in brightness approximately every three days.

The Milky Way band across the sky winds its way from southwest to northeast, straddling the western horizon so it does not cross the sky. Hence, this month most of the sky will appear to have rather few stars because it is well away from the bright band. 

The International Space Station (ISS) can be seen crossing right across the centre of the sky from 7 pm to 7:07 pm rising from southwest horizon and disappearing in the northeast horizon.  The Chinese Tiangong space station will be climb high to 61 degrees elevation on Saturday, November 24 rising from northwest at 7:20 and setting in the southeast horizon at 7:26 pm. ISS is seen extremely bright while Tiangong, (which is much smaller than ISS), shines dimmer but still bright enough to be seen clearly.  Visit www.heavens-above.com for exact timings and more satellites.

See November Sky Map below.