To budding astronomers.
A difference between true velocity and proper velocity. Proper velocity (proper motion) is the motion of a star apparent to the center-of-mass of the solar system. That is, how fast any object (a star) is moving wrt the sun’s position. (in terms of its center-of-mass)
So if a star is close to sun, its true velocity might be as much as it is, but proper velocity can be larger. Proper velocities are often larger when stars are closer, an useful fact in Astronomy.
(How proper velocity is eg useful in Astronomy, should be a good essay type question in Indian University exams, in the course of astronomy, but rather its more useful to remove essay type questions from Exams of University and such essay should be written by students as blogs, and the best blogs can be rewarded, Change should be brought to our education system by innovative thinking and not just by lecturing on outdated spiritual discourses) More…
How does the word saturnine derives ! if you care why words derive !
Saturnine might have had originated in the fact that Saturn’s Equinoxes are month long darkness (lack of sunshine for weeks altogether) as Saturn tilts away from sun (and toward sun) for 90 degree (Earth’s 23.44 degree only) ! Thats means parts of sun will get no sun-light for several weeks in the culmination of these Saturnine equinoxes.
So saturnine means a person who is gloomy or melancholic. ( — perhaps at-least for longer duration.)
I learned this because I was playing with words when grammar of my computer showed the word and I checked its meaning, I was although writing about equinox of Saturn, I came to learn this, cool is it?
Western Scientists did not care to tell the western astrologers, that, there is something called precession-of-equinox and motion of star relative to us. But in ancient times, its clear, the Indian scientists would have cared to tell this, to the Indian astrologers of those times, that, there is something called equinox-precession and apparent motion of stars wrt us, bam, the astrologers corrected their hokum machines, and we have an advanced astrology system today, but not an advanced scientific society. Perhaps they should not have told, we would have become a far better scientific society. More…
Soon India will launch its navigation satellite on October 10. Its the 3rd of the 7 that India will set on voyage above Indian Nation’s geo-spatial surface, all of which will be set to function in their orbit by next year. India has taken its strides into space.
“This will provide terrestrial, aerial and marine navigation accurately and help disaster management, vehicle tracking and fleet management, mobile phone tracking, mapping of terrain as well as air and sea navigation.”
Despite of the fact that theoretically we have better than mm range accuracy … More…
Take a chicken tikka stick. (you have seen them right? a few pieces of raw chicken is pierced into a stick)
Now ask yourself the question. How to get it minimally and maximally heated up by the fire from sun. If its minimally heated its winter and if its maximally heated its summer.
Now there are 3 primary parameters that influence the situation. One is called distance from the oven that sun is. Two any change that can be made to this distance is governed by two parameter. one when along a particular direction when we look at the oven how far it is? That distance can be changed a lot due to relative motion of earth and sun. Lets say therefore we will hold the chicken stick quite straight so it goes as straight as we stand on a given location on earth. Thats called a perpendicular in some poor mathematicians dictionary. More…
Yes it is indeed winter but you wouldn’t know until the sun sets when suddenly there is a cool feeling. The day weather is still not very cool. The abrasiveness is caused by the direct glares and flares from sun which are instantly cut off when sun sets and the equilibrium conditions are felt. Plus remember that the seasons are not due to the distance of earth from sun, between maximum and minimum, the earth varies its distance only by 3.4%. The season are due to what are called the “obliquity of ecliptic” that is; The inclination of earth in its Orbital Plane of sun (maxm; 23.44 degree).
During a variation of inclination of earth the sun also changes its relative distance from above a point on earth, causing what we call as season. In scientific terms we say seasons are effected due to equinoxes and sub-solar points or solstices. All together there are 4 of these points for a place on earth per year. SO any point on earth will have 2 equinoxes and 2 solstices. More…