Recent content by spossatamente

What makes the core of some chromospheric lines such as the transition at 8542 A of the infrared Ca II triplet appear in emission in the dark umbra of sunspots?

We know that solar corona is heated up although we don't know yet the mechanism. I was wondering which other type of stars, else than G2, in the main sequence suffer of the same effect? Thank you!

Hi, I was reading about magnetic reconnection in astrophysical plasma and it says that magnetic reconnection transforms magnetic energy into heat via ohmic dissipation, particle acceleration and kinetic energy. It is not clear to me the difference between particle acceleration and kinetic...

What do they mean with "faint regime", when they talk about cosmological explosions?? (e.g X-ray flashes) thnx

What does "to be opaque to pair production" mean? (I'm talking about fireball). I know what a pair production is but I can't get the crucial point: does it mean the photons don't collide? If it is so that means an opaque-to-p.p.- source have a greater luminosity (emits more photons) than a non...

Astrology? It is absurd. I collected some data (one of these is longitude of earth) to work out the declination and R.A. of Mars on April 15,2010. This is an exercise I did during a lesson of << misure astrofische>> (i'm attending the university of Ferrara) . Anyway... from the book...

you mean that it lies at an infinite distance because the radius of the celestial sphere is infinite...but you usually take its projection on the orbit of the Earth to measure the longitude... but this is not the point. Vernal point (put it into Hyperuranium or any else place i don't mind it)...

Vernal point is called in this picture <<equinozio 21-3 >> the other names are primavera= spring estate= summer autunno=autumn inverno= winter solstizio= solstice

...mmmh so on 15 april...if i am on the sun i see the Earth in Autumn but i am on the Earth so when i look at the sun it is ascending ( http://www.astro.virginia.edu/class/oconnell/astr121/im/CS-ecliptic-2-CK.jpg ) and that means we are on spring. But how can you explain that in the picture i...

That is clear but you still don't understand what is my problem. Since Aries+180°= Libra ==> in heliocentric coordinates system you start measure longitude from Libra point...

Well, if you measure 204° from Aries point along the orbit you find the Earth quite near to the Libra point, I mean the Earth is very far from 21 March... it sounds weird since the 204° angle corresponds to 15 April! Look at any terrestrial seasons figure as...

what's wrong with my picture?

Hello, in heliocentric coordinates the longitude of the Earth on april 15, 2010 is 204.91°... well I know that the longitude in ecliptic system (centered on the Earth ) is measured from the vernal equinox... if i started measure from V.E. in heliocentric system too I would find the Earth in...