Hello,
I was wayyyyyyy too busy to even think about doing the blog, I bet you were thinking that I was one of thsoe people who start something and forget it later on, no, I was a little busy..and no you don't have to go to another non - amusing (NOT THAT THIS BLOG IS ANY AMUSING ANYWAY) astronomy site to know about astronomy.
Today we're starting on Earth. Tell me..what do you know about the Earth?
My guess you will probably say the following, like I did the first time:
* It's the third planet from the Sun.
* Orbits as a mean speed of 150 million km, 1 AU.
* Only planet in out Solar System that has life.
* Has Seasons
But here are some facts about Earth:
•Mass of Earth is 6 x 10^24 kg and its density is 5,520 kg/m^3
*Earth is a oblate spheriod, it's squashed circle.
* Earth is closest to the Sun in Perihilion, which is in January, and Earth is furthest to the Sun in Aphelion, Which is in Earyl July.
You might think that seasons appear as the Earth moves towards, and away from the sun, however this is not the case, in reality northern winter takes place when the Earth is closest to the Sun. However, seasons takes places beuase fo the obliquity of the Earth.
Interior of the Earth:
Crust - Is made up of silicate rocks, Oceanic crust contains basaly, and continental crust contains granite.
Mantle - Contain liquid silicate rock (peridotite) that moves very slowly.
Outer Core - Liquid Iron, and lighter elements.
Inner core – solid iron-nickel alloy at temperature of 6400 K, similar to Sun’s surface.
Core responsible for Earth's global magnetic field
Density: continental crust <>
Monday 19 February 2007
Monday 5 February 2007
Moving Worlds
Hey Y'all..today is going to be about planets...and...you'll find out.
MOVING WORLDS..
The five planets, Mercury, Venus, Mars, Jupiter and Saturn are known as 'wandering stars' because they move among the fixed stars.
Confined to zodiacal constellations which span the ecliptic – orbital inclinations(the angle between the orbital plane of a planet and another given plane, usually the ecliptic) similar to that of Earth.
The motion and appearance of planets depends on the distance from the sun or whether it's inside or outside the Earth's orbit.
Inferior Planets
Planets closer to the Sun and the Earth are called inferior planets, we are able to see the full phases of the inferior planets like the moon.Inferior planet directly between Earth and Sun – inferior conjunction – large angular diameter but ‘new’ phase so invisible except during transit.
Retrograde motion
Apart from Pluto, all the other planets move within the zodiac constellations and remain near to the ecliptic.
Inferior planets move east to west then west to east as they move around Sun.
Long-term movement of superior planets is from west to east – this is direct motion.
Around opposition superior planets appear to loop as they temporarily move from east to west – this is retrograde motion.
Stationary points are where planet apparently changes direction.
Retrograde motion explained by considering relative orbital speeds of superior planets and Earth – only naturally explained by heliocentric model of Solar System.
Superior planets move more slowly in orbits around Sun, so Earth catches up with them as two planets move towards opposition.
Direct motion of superior planet slows then planet appears to move backwards as Earth overtakes.
Once Earth has passed planet it appears to resume direct motion.
If you didn't get that you get in the picture below:
That is it!!
I'm just going to continue adoring my new hair cut..lol!
_____________________________________________
Simplicity is the ultimate sophistication. Leonardo DA Vinci
MOVING WORLDS..
The five planets, Mercury, Venus, Mars, Jupiter and Saturn are known as 'wandering stars' because they move among the fixed stars.
Confined to zodiacal constellations which span the ecliptic – orbital inclinations(the angle between the orbital plane of a planet and another given plane, usually the ecliptic) similar to that of Earth.
The motion and appearance of planets depends on the distance from the sun or whether it's inside or outside the Earth's orbit.
Inferior Planets
Planets closer to the Sun and the Earth are called inferior planets, we are able to see the full phases of the inferior planets like the moon.Inferior planet directly between Earth and Sun – inferior conjunction – large angular diameter but ‘new’ phase so invisible except during transit.
Inferior planet on opposite side of Sun from Earth – superior conjunction – ‘full’ phase but small angular diameter.
Elongations
Mercury and Venus best viewed at greatest elongations - maximum angular distance from Sun and 50% phase so half of visible hemisphere is illuminated.
Greatest eastern elongation – planet to east of Sun so visible with unaided eye just after sunset.
Greatest western elongation – planet to west of Sun so visible with unaided eye just before sunrise.
Transits
If an inferior planet is directly between Earth and Sun, exactly in line with both bodies, we then will be able to see a few hours of the inferior planets as it transits the solar surface, appearing as silhouetted black disk.
Mercury and Venus best viewed at greatest elongations - maximum angular distance from Sun and 50% phase so half of visible hemisphere is illuminated
Greatest eastern elongation – planet to east of Sun so visible with unaided eye just after sunset
Greatest western elongation – planet to west of Sun so visible with unaided eye just before sunrise.
Superior Planets
Superior planets further from the Sun than the Earth - includes Mars, gas giants and Pluto. Superior planets best viewed at opposition when the Sun and Planet on opposite sides of Earth.Planets then closest the Earth, culminated at midnight and visible for all or most of the night.At conjunction superior planet is on the other side of the Sun from Earth and so is invisible.
Quadrature - planet makes Right Angle with Earth and Sun.
Superior planets do not shows appreciable phases. Mars can drop to 85% at quadrature, when fraction of illuminated hemisphere visible is at a minimum. More distant planets always show 99% or more of their lit side to us.
Retrograde motion
Apart from Pluto, all the other planets move within the zodiac constellations and remain near to the ecliptic.
Inferior planets move east to west then west to east as they move around Sun.
Long-term movement of superior planets is from west to east – this is direct motion.
Around opposition superior planets appear to loop as they temporarily move from east to west – this is retrograde motion.
Stationary points are where planet apparently changes direction.
Retrograde motion explained by considering relative orbital speeds of superior planets and Earth – only naturally explained by heliocentric model of Solar System.
Superior planets move more slowly in orbits around Sun, so Earth catches up with them as two planets move towards opposition.
Direct motion of superior planet slows then planet appears to move backwards as Earth overtakes.
Once Earth has passed planet it appears to resume direct motion.
If you didn't get that you get in the picture below:
That is it!!
I'm just going to continue adoring my new hair cut..lol!
_____________________________________________
Simplicity is the ultimate sophistication. Leonardo DA Vinci
Saturday 3 February 2007
Ptomely, Copernicus, Tycho Brahe and Kepler...
Absolutely great scientists who gave us a kick start in history..or are they just confused people?(no disrespect - love em all.)
..The Ptolemaic System
Copernicus..
1.Each planet moves around the Sun in an elliptical orbit with the Sun at one focus (the other focus is empty)
2.Each planet moves so that an imaginary line joining the centre of the planet to the centre of the Sun sweeps out equal areas in equal times. In the diagram above the planet moves from A to B and C to D in the same amount of time – the two shaded wedges have equal areas. This means that planets move fastest when closest to the Sun (perihelion) and slowest when they are furthest away (aphelion).
Well...now I'm just going to rush through about what they've done and theorised..and..you'll find out...actually I might as well show this pictures so it's much quicker and easier to understand..I'm sure the answers for why the solar system was designed to be the way it was before would be easy to understand.
Ptomely..
•Ptolemy devised widely-accepted theory to explain apparent motion of Sun and planets across sky.But... basic model could not explain retrograde motion (reverse motion of planets) of planets so several modifications were introduced.
•Ptolemy devised widely-accepted theory to explain apparent motion of Sun and planets across sky.But... basic model could not explain retrograde motion (reverse motion of planets) of planets so several modifications were introduced.
..The Ptolemaic SystemCopernicus..
Polish canon Nicholas Copernicus (1473-1543) worked on a Sun-centred or heliocentric model of the solar system from 1503 onwards
Heliocentric model was no simpler than the prevailing Ptolemaic system but did do away with equants and allowed the order of the planets from the sun to be deduced unambiguously.
Heliocentric model was no simpler than the prevailing Ptolemaic system but did do away with equants and allowed the order of the planets from the sun to be deduced unambiguously.
The Heliocentric model:
–partly explained the retrograde motion of the planets
–could not predict their exact locations, but ephemerides based on Copernicus (Prutenic Tables) were much more accurate then those based on Ptolemaic system (Alfonsine Tables).
–partly explained the retrograde motion of the planets
–could not predict their exact locations, but ephemerides based on Copernicus (Prutenic Tables) were much more accurate then those based on Ptolemaic system (Alfonsine Tables).
Tycho Brahe..
Tycho Brahe (1546-1601), Danish nobleman, founded modern observational astronomy
Motivated by the fact that a conjunction of Jupiter and Saturn predicted by Prutenic Tables (Copernican model) was in error by 2 days
Attempted to measure the distance to Mars by parallax method – unsuccessful but his detailed observations provided the raw data for Kepler to develop his laws of planetary motion
Nova (1572) – overturned Aristotelian view of perfect, unchanging Universe.
Comet (1577) – Tycho demonstrated that comets were celestial not atmospheric objects
–cometary orbit took it through crystal spheres on which celestial object were assumed to be fixed, hence crystal spheres do not exist.
Motivated by the fact that a conjunction of Jupiter and Saturn predicted by Prutenic Tables (Copernican model) was in error by 2 days
Attempted to measure the distance to Mars by parallax method – unsuccessful but his detailed observations provided the raw data for Kepler to develop his laws of planetary motion
Nova (1572) – overturned Aristotelian view of perfect, unchanging Universe.
Comet (1577) – Tycho demonstrated that comets were celestial not atmospheric objects
–cometary orbit took it through crystal spheres on which celestial object were assumed to be fixed, hence crystal spheres do not exist.
Kepler...
In the early 1600s Johannes Kepler (1571-1630), German mathematician, finally produced three laws of planetary motion: Kepler’s laws.
Worked with Tycho Brahe from 1600-1601 and on Brahe’s death took over his observatory
Using Tycho Brahe’s observations of Mars he was able firstly to deduce his equal area rule (K2), then that the planet had to have an elliptical orbit (K1).
Kepler's 1st law:
Using Tycho Brahe’s observations of Mars he was able firstly to deduce his equal area rule (K2), then that the planet had to have an elliptical orbit (K1).
Kepler's 1st law:
1.Each planet moves around the Sun in an elliptical orbit with the Sun at one focus (the other focus is empty)
Kepler's 2nd law:
2.Each planet moves so that an imaginary line joining the centre of the planet to the centre of the Sun sweeps out equal areas in equal times. In the diagram above the planet moves from A to B and C to D in the same amount of time – the two shaded wedges have equal areas. This means that planets move fastest when closest to the Sun (perihelion) and slowest when they are furthest away (aphelion).
Kepler's 3rd law:
(The maths bit)
The square of the time taken for a planet to complete one orbit is proportional to the cube of its mean distance from the Sun.
Expressed mathematically as
T^2 = kr^3
T = orbital period of planet, r = mean distance of planet from Sun (semi-major axis), k = constant
If two bodies are in orbit around the Sun or a planet their two orbits scale as
(T1 / T2)^2 = (r1 / r2)^3
where 1 and 2 are the two orbiting bodies .
Expressed mathematically as
T^2 = kr^3
T = orbital period of planet, r = mean distance of planet from Sun (semi-major axis), k = constant
If two bodies are in orbit around the Sun or a planet their two orbits scale as
(T1 / T2)^2 = (r1 / r2)^3
where 1 and 2 are the two orbiting bodies .
I think that the information here are just facts, it's better to research on their biographies to know EXACTLY how they worked it out, perhaps try wikipedia.
But anyway that is all for now!!
_____________________________________________
Simplicity is the ultimate sophistication. Leonardo DA Vinci
Gravity...Pulls me down too much into reality sometimes..
Hello people,
Unfortunate incidents happen...and no....i did not break my leg...the fortunate incident for me is that I got my work planned into a timetable, and according to the timetable, I get to post a blog only once a week...on Saturdays when I am doing my astronomy revision, and this blog is my way of revising and expressing myself and trying to get some self - esteem here (although people think my life is perfect - apart from the fact that I am a freakishly looking and extremely ugly...and yes...don't even try to make me feel better because everyone knows I'm ugly..even the flies won't circle around me....and since I can't be a model, I want to be an astrophysicist at earn a lot of money by hard work and not just by the way I look.), this is unfortunate news for you but I'll it's a chance to give yourself time (if there is people who want to look at this - i know that any sane person wouldn't!).
Anyway today is all about a gravity...and it's gonna be as quick as me eating a pie..
Newton’s Law of Gravitation states:
Any two objects of masses M and m separated from each other by a distance d, attract each other with a force F that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them
In other words ( if you have a math brain) it's:
F = GMm / d2
Where G is the gravitational constant, probably 1
F is measured in Newtons (N), M and m are measured in kg, d is measured in metres and then G has a value of 6.67 x 10^-11 Nxkg^-2xm^2
This is an inverse square law – if the distance between the two objects doubles, the force drops to a quarter of its previous value.
Gravity in the Solar System..
Just look at the picture below instead of making it all confusing..
Do you what..this would be quite confusing for you, so if you want to ask me something I'll give you my email address or I'll try to put them posting tag things..You'll see soon.
That's it for now! I think I should post the other topic as well.
_____________________________________________
Simplicity is the ultimate sophistication. Leonardo DA Vinci
Unfortunate incidents happen...and no....i did not break my leg...the fortunate incident for me is that I got my work planned into a timetable, and according to the timetable, I get to post a blog only once a week...on Saturdays when I am doing my astronomy revision, and this blog is my way of revising and expressing myself and trying to get some self - esteem here (although people think my life is perfect - apart from the fact that I am a freakishly looking and extremely ugly...and yes...don't even try to make me feel better because everyone knows I'm ugly..even the flies won't circle around me....and since I can't be a model, I want to be an astrophysicist at earn a lot of money by hard work and not just by the way I look.), this is unfortunate news for you but I'll it's a chance to give yourself time (if there is people who want to look at this - i know that any sane person wouldn't!).
Anyway today is all about a gravity...and it's gonna be as quick as me eating a pie..
Newton’s Law of Gravitation states:
Any two objects of masses M and m separated from each other by a distance d, attract each other with a force F that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them
In other words ( if you have a math brain) it's:
F = GMm / d2
Where G is the gravitational constant, probably 1
F is measured in Newtons (N), M and m are measured in kg, d is measured in metres and then G has a value of 6.67 x 10^-11 Nxkg^-2xm^2
This is an inverse square law – if the distance between the two objects doubles, the force drops to a quarter of its previous value.
Gravity in the Solar System..
Just look at the picture below instead of making it all confusing..
Do you what..this would be quite confusing for you, so if you want to ask me something I'll give you my email address or I'll try to put them posting tag things..You'll see soon.
That's it for now! I think I should post the other topic as well.
_____________________________________________
Simplicity is the ultimate sophistication. Leonardo DA Vinci
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