Dart15

YES ....... and .....NO, Maybe !

Hi, The table below is my construct (based on various sources) showing the dates for the signs of the zodiac. The first column shows the dates as they "should" be when Precession is included. The second column contains the dates as they are used in Astrology today. The third column indicates when (in the northern hemisphere - UK) it is best to observe the constellations. What I do not understand is why the dates in column 1 and column 3 are not 6 months apart given that column 1 indicates when the sun "is in" the constellation, surely means that 6 months earlier or later would be the best time to observe the constellation as it would then be on the other side of the Earth from the sun? In other words least effected by the suns light ? Dates should be now Astrology dates: Best To Observe: given Precession Column 1 Column 2 Column 3 Capricorn - Jan 20 to Feb 16 December 22 - January 19 sept - oct Aquarius - Feb 16 to Mar 11 January 20 - February 18 sept-oct Pisces - Mar 11 to Apr 18 February 19 - March 20 nov - dec Aries - Apr 18 to May 13 March 21-April 19 nov- dec Taurus - May 13 to Jun 21 April 20 - May 20 Jan - Feb Gemini - Jun 21 to Jul 20 May 21 - June 20 Jan - Feb Cancer - Jul 20 to Aug 10 June 21 - July 22 mar - Apr Leo - Aug 10 to Sep 16 July 23-August 22 mar - apr Virgo - Sep 16 to Oct 30 August 23 - September 22 may - june Libra - Oct 30 to Nov 23 September 23 - October 22 may - june Scorpius - Nov 23 to Nov 29 October 23 - November 21 June Sagittarius - Dec 17 to Jan 20 November 22 - December 21 jul - Aug

Hi All, Does anyone know how the new Gaia telescope measures distances e.g. parallax to the distant stars ? I am just interested in the basic principle. It would be easy to use the Gaia - Earth distance as the baseline for the traingle and then for Gaia and an observatory on Earth to measure the two angles to the star at the same time. That would enable the Parallax angle and the distance to be calculated. BUT, is this how it is done? I have looked at the Gaia ETSA site but there is no explanation that I can find. George

Many thanks for your replies, specially Janus who provided a very short but very usefull explanation of my particular issue. Best Regards to all. Dart15

Hi All, I understand the mathmatical and geometric principles involved in calculating the distance to the nearest stars using Parallax. However, all the examples I can find use a star that is conveniently 90 degress from the earth-sun-earth line - obviously to provide the basis for right angle triangle calculations. What I don't understand is how this method would be used for example when you look up into the night sky say in the summer and a star is to the right of the perpendicular and then when you look up again at the same star 6 months later (on the other side of the sun) and the star has moved but is still to the right of perpendicular - how could Parallax be used in this case ?- see attached diagram.

Hi, Not sure if this is a particle physics, Cosmology or physical science question - maybe all ! If light travels as a wave, why do the waves not interact with each other (like water waves do) on the way to our eyes. We should surely end up seeing just a mess of light. The question also relates to light sources in the universe where the light has been travelling with/alongside and interacting with other light sources for billions of years. So, how can we see individial (e.g. stars, galaxy's etc) light sources ? Stupid question - obvious answer ? George

If neutrinos are so difficult to detect - how does the FTL experiment manage to detect/measure them. If so, why are the other experiments around the world not "seeing" them ?

Hi, I agree with all you have said. However, what I do not understand is why there is no consideration for any elements heavier than Helium being created in the BB when the conditions are similar and all the component parts are present in abundance ? G

Hi All, I am new to this forum - so, be gentle with me. My question is this : I am told/read that all the heavy elements, that is all above Hydrogen and Helium have been created in large stars with enough heat and pressure or/and by Supernovae. These heavy elements require temperatures in a Supanovae above somewhere above 10^9 Kelvin. These temperatures occured in the very early stages of expansion of the universe - around 100 - 1000 seconds. So, why do we not think the heavy elements were created then ? George

Hi, I understand that many of the plans to explore the solar system involve using a sling shot technique around other planets to increase speed to the more distant ones. In fact Nasa used this around the moon to get back to Earth. What I have trouble understanding is where this energy comes from. In effect energy (speed) is transfered from "somewhere" to the object that is sling shot'd. Gravity is used in a very specific way - close enough to feel effect but not too close to be caught in orbit etc. The object/craft has gained energy but nothing seems to have lost energy. Surely this breaks the "conservation of energy" rule ? Confused ! George

Hi All, I am new to this forum. I have a question that may well have been explored before : "If space is expanding and it is expanding everywhere, does that mean that the space within an atom is expanding also. If so, has anyone ever calculated how long it will be before the forces holding the various parts of an atom together no longer work" Stupid question ? Dart15