Mississauga Centre RASC

87th Meeting

                                                            Members’ Night       

Day:                Friday June 22, 2007

Chair                 Randy Attwood 

Speakers:            Bob Anderson 

                           Penny Babcock

                           Randy Attwood

                             Brian Cheaney

                             Chris Malicki

                             William Callahan

                             John Marchese   

Eagle Nebula Image

Bob Anderson showed an image that he made of the Eagle Nebula, M16, using a 16 megapixel camera and 12, 20 minute exposures. He described features of the nebula and his technique in acquiring the image.

Dark Matter

Penny Babcock gave a presentation about dark matter.  Dark matter comprises 80 to 96% of the mass of the universe but cannot be seen. It is detected by its gravitational influence in galaxies and clusters of galaxies etc. The idea of dark matter is not new. In 1933 Fritz Zwicky estimated the mass of galaxies in two ways finding that the numbers differed by as much as 400 times.  He called this the missing mass problem.  In the 1980’s, rotation curves of galaxies and doppler shifts revealed that motion was not Keplerian, i.e. that the velocities did not decrease as much as would have been expected the farther one goes from the galaxy.  There is more mass present than the luminosity of a galaxy would indicate.  Another method for measuring dark matter is through gravitational lensing e.g. the galaxy cluster Abell 2218 which is observed by the bending of light.

Why look for dark matter?  Current theory of the universe holds that after the Big Bang, particles formed, then came inflation, then matter formed and then structures developed.  What will happen in the future?  Is the universe closed, open or flat?  Recent evidence suggests that the universe is increasingly expanding.  The WMAP satellite determined that the universe is flat; while the cosmic microwave background started when the big bang formed.  Fluctuations in the cosmic microwave background need dark matter to keep growing.  Dark matter on a large scale manifests as filament in the galaxy clusters. 

Three candidates for dark matter have been postulated.  Massive compact halo objects (MACHO’s) could consist of brown dwarfs, white dwarfs, neutron stars or black holes  but there don’t seem to be enough of them, or of hydrogen gas which should be detectable. Weakly interactive massive particles (WIMP’s) such as axions, neutralinos or photinos are other candidates for dark matter but they are theoretical at present. Finally, dark matter could be mimicked by a change in the force of gravity as in the MOND theory. 

The 8.4 meter large synoptic survey telescope which should be functional in Chile in 2014 and the Veritas Array in Argentina containing 4 large reflectors to detect gamma rays may be able to distinguish among the candidates for dark matter.

Public Outreach

Randy Attwood said that our club is growing rapidly and he outlined a few initiatives for observing. The RASC has an important mandate of outreach wherein we take our love of the universe and share it with others.  We have had Astronomy Day and the lunar eclipse and now it is time to expand on this.  We can have astronomy courses to have more people feel comfortable in setting up telescopes and showing the stars.  In addition, the university has asked us to pay for the use of our meeting room. In response to this, Randy and Terry met with Dr. Krull and discussed the outreach  “Science-in-the-City” program. By participating in this we could stay in the room without additional expenses.  Randy wishes to set up such an outreach program.  Then, in 2009 we will be in a position to take advantage of the International Year of Astronomy.  Randy asked for interest in participation for this.  Finally, at the RASC General Assembly in Calgary the three centres of Toronto, Mississauga and Hamilton agreed to host the 2008 assembly. We are looking for help and plan to have Phil Plait as the keynote speaker.

Telescope and binocular supports

Brian Cheaney has an 8-inch reflecting telescope and binocular crutch supports to sell and he descried them to the membership.

Archives and meeting reports

As secretary, Chris Malicki writes up the meetings of the Centre. These are posted both on the Mississauga Centre website and on Chris’ meetings site at http://ca.oocities.com/masmeetings@rogers.com/

Starfest 2007

Bob Anderson discussed the upcoming Starfest, the largest astronomy gathering held in Canada where 1000 people experience astronomy. The speakers are excellent and Bob described several from past meetings namely Story Musgrave, Terrence Dickinson and Nagel Cox.  Starfest is held near Mount Forest, ON, near the New Moon of August and boasts fairly dark skies. He read out the program for this year which is entitled “The Universe in Motion”. He encouraged people to attend.

Observing Program

William Callahan, chair of the observing committee, spoke of the results of the observing survey. The observing program should go live in September. The Yahoo group will be the way to communicate. Plans are to observe from a city site and dark site once per month.  John Marchese described the Yahoo group, options, set up etc. He emphasized that this is an important tool for communication within the club.

The Sky for July

Roy Swanson spoke about the sky for July using the Observer’s Handbook as a guide. He described planet symbols and stated that Venus will be especially bright in July.

Submitted by Chris Malicki, Secretary  Chris Malicki, Secretary                               back to Miss Centre. meeting reports page
Mississauga Centre RASC