Europe has launched the Gaia satellite - one of the most ambitious space missions in history.
The 740m-euro (£620m) observatory is going to map the precise positions and distances to more than a billion stars.
This should give us the first realistic picture of how our Milky Way galaxy is constructed.
Gaia's remarkable sensitivity will lead also to the detection of many thousands of previously unseen objects, including new planets and asteroids.
The European Space Agency (Esa) satellite is being sent up on a Soyuz rocket.
Lift-off from the Sinnamary launch complex in French Guiana was scheduled for 06:12 local time (09:12 GMT).
Gaia will be released from the rocket's upper-stage just over 40 minutes later.
The intention is to put it on path to an observing station some 1.5 million km from the Earth on its nightside - a journey that will take about a month.
Gaia has been in development for more than 20 years. It will be engaged in what is termed astrometry - the science of mapping the locations and movements of celestial objects.
To do this, it carries two telescopes that throw light on to a huge, one-billion-pixel camera detector connected to a trio of instruments.
Gaia will use this ultra-stable and supersensitive optical equipment to pinpoint its sample of stars with extraordinary confidence.
By repeatedly viewing its targets over five years, it should get to know the brightest stars' coordinates down to an error of just seven micro-arcseconds.
"This angle is equivalent to the size of a euro coin on the Moon as seen from Earth," explained Prof Alvaro Gimenez, Esa's director of science.
Gaia will compile profiles on the stars it sees.
As well as working out how far away they are, the satellite will study their motion across the sky.
Their physical properties will also be catalogued - details such as brightness, temperature, and composition. It should even be possible then to determine their ages.
And for about 150 million of these stars, Gaia will measure their velocity either towards or away from us.
This will enable scientists to use them as three-dimensional markers to trace the evolution of the Milky Way, to in essence make a time-lapse movie that can be run forwards to see what happens in the future, or run backwards to reveal how the galaxy was assembled in the past.
And because Gaia will track anything that passes across its camera detector, it is likely also to see a colossal number of objects that have hitherto gone unrecorded - such as comets, asteroids, planets beyond our Solar System, cold dead stars, and even tepid stars that never quite fired into life.
"It will allow us, for the first time ever, to walk through the Milky Way - to say where everything is, to say what everything is. It is truly a transformative mission," said Prof Gerry Gilmore from Cambridge University, UK.
How Gaia will unfurl its protective sunshield in space
A key early moment in the endeavour comes just an hour after launch.
It is at this point that Gaia must deploy the sunshield that will protect its optics from any swings in temperature and the disturbance this would introduce to the measurement task.
The unfurling is achieved through the simultaneous firing of 12 pyrotechnic devices. These will split the bolts that were used to lock the shield in a stowed configuration for launch.
It will be a high-anxiety event. A failure to "flower" would kill the mission.
By the end of the decade, the Gaia archive of processed data is expected to exceed 1 Petabyte (1 million Gigabytes), equivalent to about 200,000 DVDs of information.
This store is so vast that it will keep professional astronomers busy for decades.
It means however that there will be ample scope as well for citizen scientists to mine Gaia's data to make their own discoveries, and a number of crowdsourcing projects to facilitate this activity will get under way next year.
Gaia has been born from an enormous industrial effort. Led by Astrium satellites in Toulouse, France, it has involved more than 70 companies in 16 countries.
"Although contracts weren't signed until 2006, the Gaia idea actually began in 1991. That's astonishing - 1991, and now we're about to launch this remarkable spacecraft. What an adventure!" commented Astrium CEO Eric Beranger.
Stellar parallax
As the Earth goes around the Sun, relatively nearby stars appear to move against the 'fixed' stars that are even further away
Because we know the Sun-Earth distance, we can use the parallax angle to work out the distance to the target star
But such angles are very small - less than one arcsecond for the nearest stars, or 0.05% of the full Moon's diameter
Gaia will make repeat observations to reduce measurement errors down to seven micro-arcseconds for the very brightest stars
Sun has 'flipped upside down' as new magnetic cycle begins
The sun's magnetic field has now fully reversed its polarity, marking the midpoint of Solar Cycle 24, which will be completed in 11 years time
The sun has fully "flipped upside down", with its north and south poles reversed to reach the midpoint of Solar Cycle 24, Nasa has said.
Now, the magnetic fields have once again started moving in opposite directions to begin the completion of the 22 year long process which will culminate in the poles switching once again.
"A reversal of the sun's magnetic field is, literally, a big event," said Nasa's Dr. Tony Phillips.
"The domain of the sun's magnetic influence (also known as the 'heliosphere') extends billions of kilometers beyond Pluto. Changes to the field's polarity ripple all the way out to the Voyager probes, on the doorstep of interstellar space."
To mark the event, Nasa has released a visualisation of the entire process.
Youtube Video
At the beginning, in 1997, the video shows the sun with its positive polarity on the top (the green lines), and the negative polarity on the bottom (the purple lines).
Over the next 11 years, each set of lines gradually move toward the opposite pole, eventually showing a complete flip.
By the end, both set of lines representing the opposing magnetic fields begin to work their way back, which will eventually culminate in the completion of the full 22 year magnetic solar cycle in approximately 11 years, before the whole process starts over again.
"At the height of each magnetic flip, the sun goes through periods of more solar activity, during which there are more sunspots, and more eruptive events such as solar flares and coronal mass ejections," said Nasa's Karen C. Fox.
"Cosmic rays are also affected," added Dr. Phillips. "These are high-energy particles accelerated to nearly light speed by supernova explosions and other violent events in the galaxy.
2014 Supermoon Dates: Two New Moons Coming in January
As the year 2014 enters, five supermoon dates are expected and the first one will be on January 1. January 1 will have the first new moon of the month before another one, which will be on January 30 making January 2014 the only month with two supermoons until January 2018 according to EarthSky.
What is a supermoon? Basically, a supermoon is when the moon makes its closest approach to Earth in its orbit than usual, which is seen clearly when there's full moon.
"So, the moon may seem bigger although the difference in its distance from Earth is only a few per cent at such times," Dr. James Garvin said on the space agency's website, a chief scientist at NASA's Goddard Space Flight Centre. "It is called a supermoon because this is a very noticeable alignment that at first glance would seem to have an effect. The 'super' in supermoon is really just the appearance of being closer."
According to EarthSky, because of the closeness of the supermoon to the Earth, it can appear "as much as 14% larger in the sky and 30% brighter to our eyes than at minimum size and brightness,"
Supermoon commonly does not impact much, but it can still bring higher tides than usual.
EarthSky also reported that the word supermoon was first used by astrologer Richard Nolle over 30 years ago and is now popular again. Nolle stated that a supermoon is "a new or full moon which occurs with the moon at or near (within 90% of) its closest approach to Earth in a given orbit."
This usually means that in average, there are four to six supermoons per year.
The other supermoons in 2014 will occur on July 12, August 10, and September 9.
While on August 10, the moon will be closest to the Earth.
Perigee full moon or perigee new moon was the former name of supermoon before it became supermoon. Perigee literally means "near Earth."
Quadrantid Meteor Shower Peaks January 3: How To Go See 2014's First Shooting Stars
Astronomers predict that the shower will peak between Jan. 3 and Jan. 4 this year. The International Meteor Organization thinks the peak will come at about 19:30 Universal Time on Jan. 3 - about 2:30 in the afternoon for those on the U.S. East Coast, meaning that people across the Atlantic will likely have a better view. But peak predictions are not always 100 percent accurate, so it may still be possible to catch some meteors on Friday night in the U.S. And seeing the shower will be made easier thanks to the fact that that night's moon will be just a slim crescent that sets early in the evening.
If you can get to an area with open sky, away from the lights of the city, you may see some of the characteristic Quadrantid fireballs after sunset on Jan. 3. While most meteor showers peak over two days, the window of opportunity is much shorter for the Quadrantids, just a few hours.
Hubble Space Telescope spots clouds on alien worlds
Astronomers have spotted clouds in the atmospheres of two planets outside our solar system, with a pair of research papers suggesting that these sorts of cloudy alien worlds might be far more common than previously thought.
Two separate research teams examined data from the Hubble Space Telescope relating to the extrasolar planets GJ 1214b and GJ 436b. Located 42 light-years away from Earth, GJ 1214b is a prime example of a 'super-Earth' planet whilst GJ 436b - 36 light-years away - is a 'warm Neptune'.
Super-Earths are planets with a mass between that of Earth and Neptune (GJ 1214b has a radius 2.7 times that of Earth) whilst warm Neptunes are, as the name suggests, hot versions of our own Neptune. They maintain a close orbit to their star of less than one astronomical unit (roughly the average distance from the Earth to the Sun, or around 90,000,000 miles).
"We always knew the clouds must be there for some planets, but now we have a wave of results telling us that clouds are actually very common," said Heather Knutson, a planetary astronomer at the California Institute of Technology in Pasadena and lead author of the paper studying GJ436b, to Space.com.
The composition of these planets are studied when they pass in front of their stars. When this 'transit' occurs, the molecules that make up the exoplanet's atmosphere block off different parts of the light spectrum. By recording which sections make it through and which don't astronomers can deduce what the planets are made of.
For GJ 1214b these observations were notable for revealing no signs of an atmosphere at all. It was thought that this could mean that thick clouds were blocking the starlight or that the planet was made up of relatively heavy molecules such as water, with gravity compressing this substance into a thin, dense layer.
This most recent study, led by Laura Kreidberg of the University of Chicago in Illinois, has shown that there "have to be clouds" present. However, these would be utterly alien to the clouds found on Earth, and are likely to be made up of compounds such as zinc sulphide or potassium chloride, rather than our own, comparatively homely, mixture of water droplets and ice.
The sun 'flips upside down': 10 surprising facts about our star
As the sun completes its 11 year cycle, culminating in its north and south poles 'flipping', take a look at some of the other interesting facts about the star, as well as some incredible images
The fact that the sun's magnetic field reverses every eleven years, isn't the only surprising thing about our closest star. Take a look at some other incredible facts about the ball of fire that gives life to Earth.
1. The sun makes up 99.8 per cent of the mass of the entire solar system. The sun's core, although it only makes up around 2 percent of the sun's volume, holds nearly half of its mass.
2. The sun is travelling at 220 kilometres per second. It takes the 225-250 million years to complete an orbit of the centre of the Milky Way.
3. With a circumference of 2,715,395.6 miles, one million Earths could fit inside the sun.
4. As the sun has no solid body - it is made up of 92.1 percent hydrogen and 7.8 percent helium - different parts of the sun rotate at different rates. At the equator, the sun spins once about every 25 days, but at its poles the sun rotates once on its axis every 36 Earth days.
5. One day, the sun will be about the size of Earth. After its red giant phase - when the sun would have expanded, consuming Mercury, Venus and Earth - the sun will collapse, retaining its enormous mass, but shrinking to the approximate volume of our planet to become a white dwarf. It is currently categorised as a yellow dwarf and at 4.5 billion years old, is currently middle aged.
6. The sun's magnetic fields generate solar wind - streams of charged particles, which travel through the solar system at 450 kilometres per second. The winds cause radio interference, the northern lights and tails on comets, as well as alter the trajectory of space crafts.
7. A complex internal mechanism about which little is known causes the reverse in polarity.
8. The temperature at the sun's core is about 15 million °C while its surface temperature is 5500 °C
9. Sunspots - visible dark patches that appear on the sun's surface - are temporary phenomena whereby intense magnetic activity form areas of reduced surface temperature.
10. Solar flares shoot out from the sun's surface during when magnetic energy is released by the during magnetic storms. They are the most violent eruptions in the solar system.
The planet, known as KOI-314c, is the same weight as Earth, but much larger and has a surface temperature of 104C
Scientists have stumbled upon a planet considered Earth's 'twin' in another solar system 200 light years away.
Known as KOI-314c, the planet is the same weight as Earth, but is 60% larger.
The planet is also much hotter than Earth, with scientists estimating its surface temperatures to be around 104C - unsupportive of most life forms on Earth.
KOI-314c is suspected to have a thick gaseous atmosphere, making the planet only 30% denser than water.
However, despite a similar weight, astronomers said the planet is not considered "Earth-like".
"This planet might have the same mass as Earth, but it is certainly not Earth-like," said lead astronomer Dr David Kipping, from the Harvard-Smithsonian Centre for Astrophysics in the US.
He added: "It proves that there is no clear dividing line between rocky worlds like Earth and fluffier planets like water worlds or gas giants."
Scientists made the discovery by accident while searching for moons using the powerful Kepler space telescope.
"When we noticed this planet showed transit timing variations, the signature was clearly due to the other planet in the system and not a moon," said Dr Kipping.
"At first we were disappointed it wasn't a moon, but then we soon realised it was an extraordinary measurement."
Evidence of the new planet was presented at the annual meeting of the American Astronomical Society in Washington DC.
One thing I like about Astronomy is that its incredibly humbling. We are nothing but a speck of dust compared to the rest of the universe! Check this out:
This cannot be undone and I am sure it will be greatly appreciated.
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