Where did the universe come from?

We know that at the moment space is expanding and this means that in the past everything was close together, here the Big Bang theory has his origins.

We can see the moment when the universe was very packed together at the period of 1 second after the Big Bang and we can also here the echo of that period.

The problem begins when the universe is even younger then 1 second because the only vision of that period comes from our theories, due to the fact that we can't reproduce that period in a laboratory yet. The drawback of these theories is the fact that we have to use quantum (because of the small objects we have to deal with) and relativity (because of the massive objects that we have to deal with). However, those theories do not work together.


This is the background radiation as we see it










Two conversions of ripples in the radiation that have been converted to the frequencies that we can hear.

 

| la 1:44 PM | 0 comentarii

Modern mysteries of astronomy

In this post I will try to present the 11 mysteries of modern astronomy and in the future I will discuss them individually.

There are the 3 well renowned mysteries:

And the 8 less renowned ones:
  • How did Black Holes get so big?
  • Where are the dwarf galaxies?
  • Sedna's Orbit
  • Lack of Tidal Locking
  • Long Stellar Pulsation
  • Planet Formation
  • Jets
  • Comet Tails

| la 10:01 AM | 0 comentarii

Neptune

Diameter: 49,500 kilometers
Temperature: -200 °C (72 K)
Orbit: Takes 164.8 Earth-years to complete an orbit.
Average Distance:  4,500 million kilometers - 2,794.4 (millions of miles) from Sun
Mass:  17.15 Earth-masses
Moons: 13
Period of Rotation: 17.7 hours

Missions to Neptune:

Voyager 2's closest approach to Neptune occurred on August 25, 1989

Neptune in history:


Galileo was the first to observe Neptune on December 28, 1612 and again on January 27, 1613 but in both occasions, Galileo mistook Neptune for a fixed star. During the period of his first observation in December 1612, Neptune was stationary in the sky because it had just turned retrograde that very day. This apparent backward motion is created when the orbit of the Earth takes it past an outer planet.  In July 2009 University of Melbourne physicist David Jamieson announced new evidence suggesting that Galileo was at least aware that the star he had observed had moved relative to the fixed stars.


In 1821, Alexis Bouvard published astronomical tables of the orbit of Neptune's neighbor planet Uranus. Subsequent observations revealed substantial deviations from the tables, leading Bouvard to hypothesize that an unknown body was perturbing the orbit through gravitational interaction. In 1843, John Couch Adams began work on the orbit of Uranus using the data he had. Via James Challis, he requested from Sir George Airy, the Astronomer Royal, who sent the data in February 1844. Adams continued to work on this in 1845-1846 and produced several different estimates of new planet, but did not respond to a request from Airy about the orbit of Uranus.

In 1845–46, Urbain Le Verrier, independently of Adams, developed his own calculations but also experienced difficulties in stimulating any enthusiasm in his compatriots. In June 1846, upon seeing Le Verrier's first published estimate of the planet's longitude and its similarity to Adams's estimate, Airy persuaded Cambridge Observatory director James Challis to search for the planet. Challis vainly scoured the sky throughout August and September.

Meantime, Le Verrier by letter urged Berlin Observatory astronomer Johann Gottfried Galle to search with the observatory's refractor. Heinrich d'Arrest, a student at the observatory, suggested to Galle that they could compare a recently drawn chart of the sky in the region of Le Verrier's predicted location with the current sky to seek the displacement characteristic of a planet, as opposed to a fixed star. The very evening of the day of receipt of Le Verrier's letter on September 23, 1846, Neptune was discovered within 1° of where Le Verrier had predicted it to be, and about 12° from Adams' prediction. Challis later realized that he had observed the planet twice in August, failing to identify it owing to his casual approach to the work.

In the wake of the discovery, there was much nationalistic rivalry between the French and the British over who had priority and deserved credit for the discovery. Eventually an international consensus emerged that both Le Verrier and Adams jointly deserved credit. Since 1966 Dennis Rawlins has questioned the credibility of Adams's claim to co-discovery and the issue was re-evaluated by historians with the return in 1998 of the "Neptune papers" (historical documents) to the Royal Observatory, Greenwich. After reviewing the documents, they suggest that "Adams does not deserve equal credit with Le Verrier for the discovery of Neptune. That credit belongs only to the person who succeeded both in predicting the planet's place and in convincing astronomers to search for it."

Shortly after its discovery, Neptune was referred to simply as "the planet exterior to Uranus" or as "Le Verrier's planet". The first suggestion for a name came from Galle, who proposed the name Janus. In England, Challis put forward the name Oceanus.

Claiming the right to name his discovery, Le Verrier quickly proposed the name Neptune for this new planet, while falsely stating that this had been officially approved by the French Bureau des Longitudes. In October, he sought to name the planet Le Verrier, after himself, and he had loyal support in this from the observatory director, François Arago. This suggestion met with stiff resistance outside France. French almanacs quickly reintroduced the name Herschel for Uranus, after that planet's discoverer Sir William Herschel, and Leverrier for the new planet.

Struve came out in favour of the name Neptune on December 29, 1846, to the Saint Petersburg Academy of Sciences. Soon Neptune became the internationally accepted name. In Roman mythology, Neptune was the god of the sea, identified with the Greek Poseidon. The demand for a mythological name seemed to be in keeping with the nomenclature of the other planets, all of which, except for Earth, were named for Greek and Roman mythology.

Most languages today, even in countries that have no direct link to Graeco-Roman culture, use some variant of the name "Neptune" for the planet; in Chinese, Japanese and Korean, the planet's name was literally translated as "sea king star" (海王星), since Neptune was the god of the sea.




Neptune internal structure: 


Neptune's internal structure resembles that of Uranus. Its atmosphere forms about 5 to 10 percent of its mass and extends perhaps 10 to 20 percent of the way towards the core, where it reaches pressures of about 10 GPa. Increasing concentrations of methane, ammonia and water are found in the lower regions of the atmosphere.

The mantle reaches temperatures of 2,000 K to 5,000 K. It is equivalent to 10 to 15 Earth masses and is rich in water, ammonia and methane. As is customary in planetary science, this mixture is referred to as icy even though it is a hot, highly dense fluid. This fluid, which has a high electrical conductivity, is sometimes called a water-ammonia ocean. At a depth of 7000 km, the conditions may be such that methane decomposes into diamond crystals that then precipitate toward the core. The mantle may consist of a layer of ionic water where the water molecules break down into a soup of hydrogen and oxygen ions, and deeper down superionic water in which the oxygen crystallises but the hydrogen ions float around freely within the oxygen lattice.

The core of Neptune is composed of iron, nickel and silicates, with an interior model giving a mass about 1.2 times that of the Earth. The pressure at the centre is 7 Mbar (700 GPa), millions of times more than that on the surface of the Earth, and the temperature may be 5,400 K.


Rings of Neptune:




Neptune has a planetary ring system, though one much less substantial than that of Saturn. The rings may consist of ice particles coated with silicates or carbon-based material, which most likely gives them a reddish hue. The three main rings are the narrow Adams Ring, 63000 km from the centre of Neptune, the Le Verrier Ring, at 53000 km, and the broader, fainter Galle Ring, at 42000 km. A faint outward extension to the Le Verrier Ring has been named Lassell; it is bounded at its outer edge by the Arago Ring at 57000 km.

The first of these planetary rings was discovered in 1968 by a team led by Edward Guinan, but it was later thought that this ring might be incomplete. Evidence that the rings might have gaps first arose during a stellar occultation in 1984 when the rings obscured a star on immersion but not on emersion. Images by Voyager 2 in 1989 settled the issue by showing several faint rings. These rings have a clumpy structure, the cause of which is not currently understood but which may be due to the gravitational interaction with small moons in orbit near them.

The outermost ring, Adams, contains five prominent arcs now named Courage, Liberté, Egalité 1, Egalité 2 and Fraternité (Courage, Liberty, Equality and Fraternity). The existence of arcs was difficult to explain because the laws of motion would predict that arcs would spread out into a uniform ring over very short timescales. Astronomers now believe that the arcs are corralled into their current form by the gravitational effects of Galatea, a moon just inward from the ring.

Earth-based observations announced in 2005 appeared to show that Neptune's rings are much more unstable than previously thought. Images taken from the W. M. Keck Observatory in 2002 and 2003 show considerable decay in the rings when compared to images by Voyager 2. In particular, it seems that the Liberté arc might disappear in as little as one century.

| la 6:10 AM | 0 comentarii

Uranus



Diameter: 51,500 km (32,000 miles)
Temperature: -197.15 C (-322.87° F)
Orbit: Takes 84 years to complete an orbit.
Average Distance: 2,870,972,200 km (1,783,939,400 miles - 19.2 AU) from Sun
Mass: 8.6849 x 1025 kg
Moons: 27
Period of Rotation: 17.24 hours (retrograde: spins backwards compared to most other planets)

Missions to Uranus:


Voyager 2 - January 24, 1986


Uranus in history:


Uranus was mistaken at first for a star first time in 1690 by Jon Flamsteed, cataloging it as 35 Tauri, then the French astronomer Pierre Lemonnier observed it at least twelve times between 1750 and 1769.


After this Sir William Herschel observed the planet on March 13, 1781 in his garden but initially reported it om April 26, 1781 as a "comet". Herschel was using a telescope of his own design.


In his journal he recorded On March 17:  "I looked for the Comet or Nebulous Star and found that it is a Comet, for it has changed its place". When he presented his discovery to the Royal Society, he continued to assert that he had found a comet while also implicitly comparing it to a planet.

Herschel notified the Astronomer Royal, Nevil Maskelyne, of his discovery and received this flummoxed reply from him on April 23: "I don't know what to call it. It is as likely to be a regular planet moving in an orbit nearly circular to the sun as a Comet moving in a very eccentric ellipsis. I have not yet seen any coma or tail to it".

While Herschel continued to cautiously describe his new object as a comet, other astronomers had already begun to suspect otherwise. Russian astronomer Anders Johan Lexell was the first to compute the orbit of the new object and its nearly circular orbit led him to a conclusion that it was a planet rather than a comet. Berlin astronomer Johann Elert Bode described Herschel's discovery as "a moving star that can be deemed a hitherto unknown planet-like object circulating beyond the orbit of Saturn". Bode concluded that its near-circular orbit was more like a planet than a comet.

The object was soon universally accepted as a new planet. By 1783, Herschel himself acknowledged this fact to Royal Society president Joseph Banks: "By the observation of the most eminent Astronomers in Europe it appears that the new star, which I had the honour of pointing out to them in March 1781, is a Primary Planet of our Solar System." In recognition of his achievement, King George III gave Herschel an annual stipend of £200 on the condition that he move to Windsor so that the Royal Family could have a chance to look through his telescopes.


Uranus internal structure: 



Uranus has a mass of roughly 14.5 times that of the Earth, making it the least massive giant planet. Its diameter is slightly larger than Neptune's at roughly four times Earth's. A resulting density of 1.27 g/cm3 makes Uranus the second least dense planet, after Saturn. This indicates that it is made primarily of various ices, such as water, ammonia and methane. The total mass of ice in Uranus's interior is not precisely known, it must be between 9.3 and 13.5 Earth masses. Hydrogen and helium constitute only a small part of the total, with  between 0.5 and 1.5 Earth masses, the remainder of the non-ice mass, 0.5 to 3.7 Earth masses, is accounted for by rocky material.


In standard model of Uranus internal structure consists of three layers: a rocky (silicate/iron-nickel) core in center, an icy mantle in the middle and an outer gaseous hydrogen/helium envelope. The core is relatively small, with a mass of only 0.55 Earth masses and a radius less than 20% of Uranus's; the mantle comprises the bulk of the planet, with around 13.4 Earth masses, while the upper atmosphere is relatively insubstantial, weighing about 0.5 Earth masses and extending for the last 20% of Uranus's radius. Uranus's core density is around 9 g/cm3, with a pressure in the center of 8 million bars and a temperature of 5000K. The ice mantle is not in fact composed of ice in the conventional sense, but of a hot and dense fluid consisting of water, ammonia and other volatiles. This fluid has a high electrical conductivity is sometimes called a water-ammonia ocean. The bulk compositions of Uranus and Neptune are very different from those of Jupiter and Saturn, with ice dominating over gases, hence justifying their separate classification as ice giants. There may be a layer of ionic water where the water molecules break down into a soup of hydrogen and oxygen ions and deeper down superionic water in which the oxygen crystallizes but the hydrogen ions move freely within the oxygen lattice.

Other models are also in satisfaction with the observations. For instance, if substantial amounts of hydrogen and rocky material are mixed in the ice mantle, the total mass of ices in the interior will be lower and correspondingly, the total mass of rocks and hydrogen will be higher. Presently available data does not allow science to determine which model is correct.


Rings of Uranus:





Uranus has a complicated planetary ring system (the second such system to be discovered in our Solar System after Saturn's). The rings composition is from a extremely dark particles, which vary in size from micrometers to a fraction of a meter. All rings are extremely narrow, except two of them. The rings are probably quite young and the dynamics considerations indicate that they did not form with Uranus so the matter in the rings may have been part of a moon or moons that was shattered by high speed impacts.

| la 7:28 AM | 0 comentarii

Saturn


Diameter: 120,660 km. It is about 10 times larger than our Earth
Temperature: –178°C
Distance from Earth: At its closest, Saturn is 1190.4 million km
Atmosphere: Hydrogen and helium
Surface: consists of liquid and gas.
Rotation of its axis: 10 hours, 40 min, 24 sec
Rotation around the Sun: 29.5 Earth years

Missions to Saturn:

 -  
Pioneer 11 in September 1979

-
  Voyager 1 in November 1980
-  Voyager 2 in August 1981

 - Cassini–Huygens spacecraft in July 1, 2004



Saturn in History: 

Because is visible whit the naked eye, Saturn was known from ancient times:


Babylonian astronomers systematically observed and recorded the movements of Saturn. In Roman mythology, the god Saturnus, from whici the planet takes its name, was the god of agricultural and harvest sector. They considered Saturnus the equivalent of  the Greek god Cronus so as usual Greeks associates a particular star whit a god and the Romans followed suit.


In Hindu astrology, Saturn is known as "Shani", the one that judges everyone based on the good and bad deeds performed in life. In the 5th century CE, the Indian astronomical text Surya Siddhanta estimated the diameter of Saturn whit a remarkable precision by more then 99%. Ancient Chinese and Japanese designated the planet Saturn as the earth star, based on the Five Elements which were traditionally used to classify natural elements.

In Hebrew, Saturn is called "Shabbathai" and in ottoman Turkish, Urdu and Malay, its name is "Zuhal", derived from Arabic.

European observations (17th–19th centuries):
Galileo was first to saw the ring as two moons on Saturn's sides and only when Christian Huygens used greater telescopic magnification this notion was refuted. Huygens was also the one ho discovered Saturn's moon Titan. Giovanni Domenico Cassini discovered four other moons: Iapetus, Rhea, Tethys and Dione. He also discovered the gap now known as the Cassini Division.

Almost 150 ears later William Herschel discovered two further moons, Mimas and Enceladus.

And in 1899 William Henry Pickering discovered Phoebe, a highly irregular satellite that does not rotate synchronously with Saturn as the larger moons do. Phoebe was the first such satellite found and it takes more than a year to orbit Saturn in a retrograde orbit. During the early 20th century, research on Titan led to the confirmation in 1944 that it had a thick atmosphere, a feature unique among the solar system's moons.


Saturn internal structure: 


Saturn's internal structure is similar to that of Jupiter, having a small rocky core surrounded mostly by hydrogen and helium. The rocky core is similar in composition to the Earth, but much more dense. Core is surrounded by a thicker liquid metallic hydrogen layer, followed by a liquid hydrogen/helium layer and a gaseous region is estimated to be about 9-22 times the mass of the Earth. The temperature of Saturn's core is about 11,700  °C and radiates 2.5 times more energy into space than it receives from the Sun. Most of this extra energy is generated by the Kelvin - Helmholtz mechanism (slow gravitational compression), but this alone may not be sufficient to explain Saturn's heat production. It is possibely that an additional mechanism might be at play whereby Saturn generates some of its heat through the "raining out" of droplets of helium deep in its interior, thus releasing heat by friction as they fall down through the lighter hydrogen. The interior is estimated to be about 25,000 km across.



Saturn atmosphere:


Saturn has an outer atmosphere of 96.3% molecular hydrogen and 3.25% helium. Also have been detected trace amounts of ammonia, acetylene, ethane, phosphine and methane.
The upper clouds on Saturn are made of ammonia crystals, while the lower level clouds apper to be composed of either ammonium hydrosulfide or water. The atmosphere of Saturn is significantly deficient in helium relative to abundance of the elements in the Sun.

Rings of Saturn:




Saturn is best known for its planetary ring, which makes it the most visually remarkable object in the solar system. The rings extend from 6,600 km to 120,700 km above Saturn's equator.
Composition of the rings is a 93$ water ice with a smattering of thlion impurities and 7% amorphous carbon. The particles that make up the ring range in size from specks of dust up to 10m..
There are two main theories about the formation of the rings. One of them is that the rings are remnants of a destroyed moon of Saturn and the second theory is that the rings are left over from the original nebula material from which Saturn formed. Some ice in the central rings comes from the moon Enceladus' ice volcanoes.


Beyond the main rings at a distance of 12 million km from the planet is the spare Phoebe ring, which is tilted at an angle of 27°  to the other rings and like Phoebe, orbits in retrograde fashion. Some of the moons of Saturn act as shepherd moons to keep the planetary ring stable and prevent them from escaping. Pan and Atlas, two of Saturn moons, cause weak, linear density waves in Saturn's rings that have yielded more reliable calculations of their masses.


The age of these planetary rings is probably hundreds of millions of years old (in contrast to previous thoughts that the rings formed alongside the planet when it formed billions of years ago) and their fate include spiraling inward towards the planet, or the boulders forming the rings colliding with each other and disappearing.





| la 10:55 AM | 0 comentarii