2011 has been quite a year, both terrestrial and otherwise. This week sees the last of the big scheduled astronomical happenings of the year in the form of the Geminid meteor shower.
This shower is one of the yearly standbys along with the Perseids that are always sure to produce. The Geminids have a long peak centered on the morning of December 14th when an idealized Zenithal Hourly Rate (ZHR) of up to 120 meteors per hour may be seen.
Problems will arise, however, from an 82% illuminated waning gibbous Moon in the adjacent constellation of Cancer. Rising roughly around 10PM local on the night of the peak, this makes for the worst possible Moon phase as it’ll be high and bright in the early AM hours, just as the meteor shower is getting into high gear. But as always, I wouldn’t let that stop you from looking! (more…)
This artist's conception illustrates Kepler-22b, a planet known to comfortably circle in the habitable zone of a sun-like star. Image credit: NASA/Ames/JPL-Caltech
NASA’s Kepler mission has confirmed its first planet in the “habitable zone,” the region where liquid water could exist on a planet’s surface. Kepler also has discovered more than 1,000 new planet candidates, nearly doubling its previously known count. Ten of these candidates are near-Earth-size and orbit in the habitable zone of their host star. Candidates require follow-up observations to verify they are actual planets.
The newly confirmed planet, Kepler-22b, is the smallest yet found to orbit in the middle of the habitable zone of a star similar to our sun. The planet is about 2.4 times the radius of Earth. Scientists don’t yet know if Kepler-22b has a predominantly rocky, gaseous or liquid composition, but its discovery is a step closer to finding Earth-like planets. (more…)
On the night of 17/18 November 2011 the Leonids meteor shower reaches its peak. This annual performer is associated with Comet Temple-Tuttle, which orbits the Sun once every 33 years leaving a trail of debris as it goes. Once a year the Earth passes through this trail, and we see a meteor shower.
Leonids 2001
This year’s Leonids shower is hampered by the last quarter Moon which sits just to the right of the radiant of the Leonids, in Leo. Despite this there is good reason to observe the shower this year, as the International Meteor Organisation suggest there might be as many as three peaks of activity.
Throughout November the rate of Leonids will increase, with the main peak occurring at 0340 GMT on 18 November, at which time the Zenith Hourly Rate may be 20+. For observers in the UK, observing under cloudless skies, away from light pollution, this translates as an hourly rate of ~14, but the Moon will interfere and reduce this value somewhat. Two other peaks may also occur, at ~2100 on November 17, and at ~2300 on 18 November, with similar rates. This means that both the nights of 17/18 and 18/19 November may offer good opportunites to observe this shower.
The Leonids has the distinction of being the most dramatic meteor shower that I’ve ever seen, as I observed the Leonid meteor storms every year from 1998 to 2002, when we saw hundreds of meteors each night at the peak of the shower. These storm peaks are predictable, and occur every 33 years, associated with the pass of comet Temple Tuttle, as it refreshes the trail of debris that cause the meteors. The next pass of Temple Tuttle is due 2031, so we’ve a long wait for the next storm.
Interestingly, the Leonid storm of 1833 was truly stunning, with rates estimated to be around 100,000 per hour across North America.
To view the Leonids, find a dark spot, away from light pollution, sit on a reclining deck chair facing as large an area of the sky as you can manage, wrap yourself in a blanket, and enjoy the view. For observers in the UK the meteor shower radiant will rise around 2200 GMT on 17 November and will be high in the SE by 0400 on 18 November.
Watch the first Soyuz launch from Guiana Space Center (CSG) in French Guiana
A new countdown for Soyuz’ first flight from the Spaceport
October 20, 2011 10:30:26 a.m. UT – Soyuz Flight VS01
The countdown to Soyuz’ maiden flight from French Guiana will resume for a liftoff tomorrow morning after work on the launch pad resolved a ground support system anomaly that postponed the historic mission for 24 hours.
This anomaly was identified as a leak in a launch pad pneumatic system responsible for the programmed disconnection of Soyuz’ third stage fueling lines before the vehicle lifts off.
With the issue resolved, the liftoff is now set for October 21 at 7:30:26 a.m. local time in French Guiana – a precise moment that enables the payload of two Galileo satellites to be injected into their proper orbital plane.
Soyuz’ 3-hr. 49-min. flight from the Spaceport will inject the In-Orbit Validation (IOV) spacecraft for Europe’s Galileo satellite navigation system into a 23,222-km. circular medium-Earth orbit, inclined 54.7 degrees.
Weighing approximately 700 kg. each, these satellites – along with two others to be lofted by Soyuz in 2012 – will form the operational nucleus of Europe’s full 30-satellite Galileo navigation constellation, which is being developed in a collaborative program involving the European Space Agency and European Union
With the Soyuz launcher operating out of the Guiana Space Center (CSG) in French Guiana, Arianespace is the only launch services provider in the world capable of launching all types of payloads to all orbits.
The “Soyuz in French Guiana” project covers three main aspects:
– Construction of launch facilities, including a launch pad identical to those used in Kazakhstan and Russia.
– Launcher modifications needed for operation from the Guiana Space Center (CSG), primarily ensuring compliance with the range safety rules at CSG and adaptation to the requirements of the launcher tracking network.
– Verification of compatibility of the Soyuz launcher with the environmental conditions in French Guiana (in particular the weather and wind conditions).
The Soyuz at CSG launch system, combining the new launch pad with a launcher that has been slightly modified in relation to the version launched from Baikonur, will be validated during the inaugural flight :
– The final countdown and actual flight through the end of the mission will enable validating the operation of all ground and launcher systems and equipment.
– This flight will also enable identifying any improvements that may be needed for the commercial operation of this new launch system.
Some time in the small hours of Friday or Saturday morning (21-22 October 2011) the Orionids meteor shower will reach its peak activity rate. The peak occurs some time around 21 October each year, but this year it’s uncertain which day it will fall on.
The Orionid's parent Comet P/Halley as taken March 8, 1986 by W. Liller, Easter Island, part of the International Halley Watch (IHW) Large Scale Phenomena Network.
Meteor showers result from the Earth passing through the trail of dust and debris left behind by a comet. In the case of the Orionids the parent object is the most famous of all the comets – Halley’s Comet.
The peak meteor rate for the Orionids is lower than some of the more spectacular showers (the Perseids in August, the Geminids in December, and the Quadrantids in January all regularly outperform the Orionids) but it is still worth looking out for.
The meteors will appear to radiate from the constellation of Orion (hence the name) but they will streak across the sky in all directions, and so you shouldn’t confine yourself to only looking towards this one constellation.
On Thursday and Friday evenings the radiant rises in the east around 2200 BST (2100 UT) and continues to rise to its highest in the south just before the sky starts to brighten at 0600 BST (0500 UT). The higher the radiant above the horizon the more meteors you will see. However a crescent Moon will rises in the east on both mornings, the light from which will drown out some of the fainter meteors.
This shouldn’t matter much to you if you’re observing from an urban or suburban area, as the man-made light pollution in the sky will do a far better job of obscuring the meteor shower than the Moon will, but for lucky observers in dark sites (and I’ll be one of them, as I’m spending the weekend on Sark, the world’s first Dark Sky Island) the Moon may interfere.
Here’s a table with estimated hourly rates based on dark skies / suburban / urban areas, at hourly intervals throughout the night, assuming a ZHR =40 throughout this period (It may be that the peak will fall outwith this period, e.g. in daylight hours, so these are best-case-scenario numbers).
Time (BST)
Radiant
Altitude
Radiant
Direction
Hourly Rate
Urban Site
Hourly Rate
Suburban Site
Hourly Rate
Dark Sky Site (if Moon not present)
2200
rises
ENE
<1
<1
<1
2300
8°
ENE
1
2
4
0000
16°
E
1
4
8
0100
24°
ESE
2
6
16
0200
33°
ESE
2
8
22
0300
40°
SE
2
9
26*
0400
46°
SSE
3
10
29*
0500
50°
S
3
11
31*
0600
50°
S
3
11
31*
* the true rates, given that the Moon is causing natural light pollution, are probably half these values.
All of these timings and altitudes are based on an observer in central Scotland. For other UK observers the values in columns 2-4 may be slightly off, but not noticeably so.
Observing Advice: wrap up warm, head out before midnight, sit youself in a reclining lawn chair, and enjoy the spectacle. The rates may pick up around 0200 BST on Thursday or Friday and may stay high until dawn.
