Galileo's discovery that changed our views

On January 7^th 1610, Galileo Galilei made an observation through his small telescope that changed our understanding of the universe. Using his self made refractor telescope with an aperture just one inch in diameter with a magnification of 15X, Galileo pointed his telescope to the bright planet Jupiter. The planet Jupiter showed up in the narrow of 15minutes of arc field of the telescope, accompanied by three satellites, Io was observed on 8^th January as his crude instrument was unable to separate Io and Europa the previous night.

There was no previous records of observations made of Jupiter through telescope and Galileo was in uncharted territory. Galileo first took these 4 objects as stars and continued his observations. The movement of Jupiter with respect to these “stars” made Galileo to think that maybe Jupiter has a retrograde loop. As he continued to track Jupiter, he observed that Jupiter did not move much with respect to other stars apart from the 4 “stars” that were close to Jupiter. One more puzzling observation was that these 4 “stars” always stayed close to the planet.

After several nights of observations Galileo came to the conclusion that these 4 objects were carried along by Jupiter and they are moons of Jupiter. This had a profound impact on our way of looking at the universe. This observation gave the Copernican theory more ground.

Galileo gave the moons of Jupiter roman numbers I,II,III and IV. The names suggested by Simon Marius is what we use now. Io (I), Europa (II), Ganymede (III) and Callisto (IV). The moons are called Galilean moons in honour of Galileo.

Here is a copy of Galileo notes translated

Credit: NASA

Centuries later we sent spacecraft to Jupiter and also took pictures of the Jovian moons. Here are close up photos of the moons and also few facts about them.

Io

Credit: NASA/JPL/University of Arizona

Io is the closest of the Galilean moons which orbits the planet at a distance of 421000km. Io is little bigger than our earth's moon. Io has a radius of 1821km, earth's moon has a radius of 1738km. Io goes around Jupiter in 1.7days. Io is the most volcanically active moon in our solar system. One of the reason for this high activity is that Io is affected by gravitation of Jupiter and high tidal forces make molten interior escape through the gaps created from the distortions caused by the tidal forces.

Europa

Credit: NASA/JPL/Ted Stryk

Europa is the second moon from Jupiter and is little smaller than our moon. The radius of Europa is around 1560km. It orbits the planet at a distance of 670000km and completes one rotation in 3.5days. The surface is covered with frozen salt water and scientists think that with the eccentric orbit of Europa there may be places where it may be possible for water to exist.

Ganymede

Credit: NASA/JPL/Ted Stryk

Ganymede is the largest moon in the solar system, larger than the planet Mercury. The radius of Ganymede is 2631km and that of Mercury is 2439km. Ganymede orbits the planet Jupiter 1070000km and completes on orbit every 7.15days. This is the only moon to be known to have magnetosphere and also its been thought the moon may have a salt water ocean that is trapped under the ice surface.

Callisto

Credit: NASA/JPL/Ted Stryk

Callisto is the last of Galilean moons and also the farthest from the planet Jupiter. Callisto orbits the planet at a distance of 1882000km and completes on rotation around the planet in 16.6days. The moon Callisto is also the third largest moon in the solar system with a radius of 2410km almost the size of Mercury. Callisto is among the most cratered objects in solar system. Scientists think that the core could have frozen as it formed and no geological activity has taken place from the past 4 billion years.

Jupiter is easy to spot these days. Just after sunset if we look you, Jupiter will be shining bright in the Zenith. No star in the region is as bright as Jupiter. The moons of Jupiter can easily be seen even with a pair of binoculars.

The James Webb Telescope.

Webb will have a large mirror, 6.5 meters (21.3 feet) in diameter and a sunshield the size of a tennis court. Both the mirror and sunshade won't fit onto the rocket fully open, so both will fold up and open once Webb is in outer space. Webb will reside in an orbit about 1.5 million km (1 million miles) from the Earth.

The James Webb Space Telescope was named after the NASA Administrator who crafted the Apollo program, and who was a staunch supporter of space science.

The Hindu : NATIONAL / KARNATAKA : Don't make light of it, say amateur astronomers

The Hindu : NATIONAL / KARNATAKA : Don't make light of it, say amateur astronomers

Milky Way Rising from Australia

E=mc²: Einstein explains his famous formula

Watch Out for Solar Sail Flares

NASA's first Earth-orbiting solar sail, NanoSail-D, is circling our planet and attracting the attention of sky watchers. Occasionally, sunlight glinting from the sail's reflective fabric produces a flash of light in the night sky. These "solar sail flares" are expected to grow brighter as NanoSail-D descends in the weeks ahead.

Read full article : http://science.nasa.gov/science-news/science-at-nasa/2011/01feb_solarsailflares/


Credits : Science@NASA

8 years since space shuttle Columbia disaster | Portal to the Universe

Even though this is the 25th anniversary of Challenger, Feb. 1 will always be the day NASA lost another seven and the first orbiter of the space shuttle program.
On Feb. 1, 2003, space shuttle Columbia disintegrated on re-entry killing all seven aboard at the end of STS-107, bringing on the second halt to the space [...]

The Orlando Sentinel Extra Edition after the Columbia disaster
Even though this is the 25th anniversary of Challenger, Feb. 1 will always be the day NASA lost another seven and the first orbiter of the space shuttle program.
On Feb. 1, 2003, space shuttle Columbia disintegrated on re-entry killing all seven aboard at the end of STS-107, bringing on the second halt to the space shuttle program.
Take a look at some of the front pages from around the nation after the tragedy.
Here’s coverage from the Orlando Sentinel from the day of the accident and the memorials and investigation that followed.
This is the main story by then space editor Michael Cabbage and Sentinel Staff Writer Robyn Suriano.
And be sure to check out the multimedia photo presentation featuring images from Orlando Sentinel photographer Red Huber.

Read full article : http://blogs.orlandosentinel.com/news_space_thewritestuff/2011/02/8-years-since-space-shuttle-columbia-disaster.html

Credits:Portal to the universe

Rakesh Sharma message from Space

Triple suns over China

New planets are a gas!

The final frontier: Gas worker Peter Jalowiczor is credited with discovering four planets

Published Date: 27 December 2010

By Colin Drury

PETER Jalowiczor is not sure if he believes in extra-terrestrial life.

Which is strange because Peter Jalowiczor has just helped discover a planet around which it may exist.

Quite a claim for a Rotherham gas worker who has never owned a telescope in his life - but a claim which has been confirmed by a team of astronomical experts from the University of California.

For Peter, of Masbrough, has been named by the centre's Lick-Carnegie Planet Search Team as a co-discoverer of four planets known as HD 31253b, HD 218566b, HD177830c and HD 99492c.

It was the hours he spent analysing thousands of figures of space data - all in his spare time, all on his two home PCs - which provided the clues for scientists to establish the existence of the huge gaseous orbs.

"It overwhelms me when I think about it," he says. "I've always been interested in astronomy and I have two science degrees but to be one of the officially recognised finders of these planets is just...I get lost for words."

Here's the science bit: in 2005, astronomers at the university released millions of space measurements collected over several decades and asked enthusiasts to make of them what they would.

Quirks in the data could signify the existence of exoplanets - that is, planets in other solar systems which cannot be seen with even the most powerful telescope because they are so far away.

From March 2007 Peter, 45, spent entire nights reading the data, working the figures, creating graphs.

THE PLANETS IN NUMBERS

HD 31253b - 466 days in its year - 172 light years away

HD 218566b - 225.7 days in its year - 98 light years away

HD177830c - 110.6 days in its year - 190 light years away

HD 99492c - 4,697 days in its year - 58 light years away

"Essentially you're looking for measurements which show a star, which is millions of miles across and light years away, to be oscillating by about 50 metres or less," the father of one explains.

"The measurements are so tiny, it puts many people off looking - even professional astronomers - but I find it fascinating."

He then sent discrepancies he discovered back to the scientists in California where they were further analysed to see if the quirks were caused by the existence of an exoplanet.

A Surprisingly Close Look at the Early Cosmos

A Surprisingly Close Look at the Early Cosmos | Portal to the Universe

Venus and Mercury gleam in the morning sky - Astronomy Magazine

Venus and Mercury gleam in the morning sky - Astronomy Magazine

Seven years on Mars… on Mars… on Mars…

Around this time seven years ago today I was doing a very good impression of a zombie, having stayed up all night to watch the heart stopping landing of the rover “Spirit” on Mars.

I had followed the whole thing live, via NASA TV, on a small RealPlayer box that kept freezing and breaking-up into a shattered kaleidescope flurry of pixels as my dial-up (yes, dial-up!!!) connection struggled to keep up with the data stream. I can’t remember how many cups of coffee I guzzled, how many packets of Maltesers I munched, how many bags of spicy Nik Naks I noshed, but they saw me through the night, and I didn’t miss a thing, not one moment. I sat there, in my criminally-uncomfortable chair, gazing at my flickering PC screen, for hours… HOURS… following the tense countdown to EDL. I remember my heart was in my mouth as the control room at JPL fell silent, a sign that EDL had started… I watched everyone’s faces for flickers and traces of emotion that might be hints that something, good or bad, had happened…
I remember tears of joy and utter, utter relief filling my eyes as the engineers and scientists and techs .

Star Party at ShivanahaLLi | Portal to the Universe

Star Party at ShivanahaLLi | Portal to the Universe

Astronomy Without A Telescope – Secular Evolution

NASA-HST

A traditional galaxy evolution model has it that you start with spiral galaxies – which might grow in size through digesting smaller dwarf galaxies – but otherwise retain their spiral form relatively undisturbed. It is only when these galaxies collide with another of similar size that you first get an irregular ‘train-wreck’ form, which eventually.

M51 - the Whirlpool Galaxy. Like most spiral galaxies, the spiral arms are really density waves. Drag forces produced by these density waves could drive the 'secular' evolution of galaxies. Credit: NASA-HST.

A traditional galaxy evolution model has it that you start with spiral galaxies – which might grow in size through digesting smaller dwarf galaxies – but otherwise retain their spiral form relatively undisturbed. It is only when these galaxies collide with another of similar size that you first get an irregular ‘train-wreck’ form, which eventually settles into a featureless elliptical form – full of stars following random orbital paths rather than moving in the same narrow orbital plane that we see in the flattened galactic disk of a spiral galaxy.

The concept of secular galaxy evolution challenges this notion – where ‘secular’ means separate or isolated. Theories of secular evolution propose that .

LHC poised for key milestone

Two beams accelerated at 3.5 TeV in the LHC

Energy record for the LHC

The bars of Geneva may well be bustling with excited physicists tonight, as the Large Hadron Collider (LHC) is now on the brink achieving a key milestone - collisions at 7 TeV.

At 5:20 a.m., two 3.5 TeV proton beams were successfully circulated in the LHC, the highest energy yet achieved in a particle accelerator.

CERN says that the first attempt to collide these beams will follow on a date to be announced in the near future. This will mark the beginning of the full LHC research programme.

Experiments will then continue at this energy until its detectors have accumulated one "inverse femtobarn" of data - roughly 10 trillion proton-proton collisions - with the run ending after two years at the latest.

If all goes to plan, CERN will then shut the LHC down in 2012 for a year or more to prepare it to go straight to maximum-energy 14 TeV collisions in 2013.

“Getting the beams to 3.5 TeV is testimony to the soundness of the LHC’s overall design, and the improvements we’ve made since the breakdown in September 2008,” says CERN’s

International Centre for Radio Astronomy Research - Imaging the Interstellar Medium

With an average density of less than 1 proton per cubic centimetre, the matter that exists between stars might seem unimportant. But in actual fact, our galaxy the Milky Way and the stars, planets and people it contains wouldn’t be here without it.
Comprised mostly of gas (~99%) and dust (< 1%), the Interstellar Medium (ISM) is described by astronomers and astrophysicists as ‘clumpy’, meaning the material has a tendency to coalesce through gravitational forces and collisions.
Throughout the ISM, massive stars, planetary nebulae and supernova explosions drive strong winds and shock waves through the medium. These mechanisms deposit energy, sustain the highly inhomogeneous state of the ISM and enrich it with heavy elements from which the next generation of stars and planets will eventually form.

                              The result of isolating the unique radiation "signatures" for each individual   pair of interfering speckles. Credit: J-P Macquart.


In recent years evidence has accumulated pointing to the existence of ultra-compact structures within the ISM, the properties of which require explanations well beyond the scope of current models. As these incredibly dense objects pass through our line of sight to a quasar or other compact radio source, they trigger Extreme Scattering Events (ESEs) resulting in large increases in the radiation received from sources beyond the object.
Most current explanations posed to explain the dense object responsible for ESEs are problematic or controversial. Several require increasing the known density of objects a thousand times for structures 0.3-1 AU in size, and dictate that they should be so over-pressured that they would simply explode. But if this were the case, these objects would be quite rare; whereas astronomical observations have shown them to be fairly common.
Until now the major obstacle to resolving these shortcomings has stemmed from a lack of observations, but recent progress made by radio astronomers has led to the first ever image of ‘speckles’ in the Interstellar Medium.
Shine a laser along a rough surface, and a circle- shaped speckle pattern will appear around the beam, corresponding to points of constructive interference between the reflected wavefronts. In the laboratory environment, information about this speckle pattern can be used to measure the properties of a reflecting surface down to scales approaching 1μm. But to apply this technique on an astronomical scale a naturally occurring cosmic laser is called for, which is where a class of objects known as ‘pulsars’ comes to the rescue.
Pulsars are highly magnetised, rotating neutron stars that emit a highly coherent beam of electromagnetic radiation. These objects are so compact that the radio-wavelength radiation emitted behaves much like an interstellar laser. But when it comes to imaging and making sense of a source heavily scattered by the turbulence of the ISM, the task is not for the fainted hearted.

                         The speckle image of Pulsar PSR B0834+06, produced using this new technique. Credit J-P Macquart.


The breakthrough to achieving this scientific feat was in realising that it is possible to isolate the radiation pattern for each individual pair of interfering speckles, or "sub-images" of the pulsar. Each pair of interfering sub-images creates an unique “signature” that changes over time and encodes information relating to the exact location of the speckles. By recording the intensity fluctuations, in both time and frequency, as the pulsar moves relative to the Interstellar Medium it is possible to generate a secondary spectrum like the one shown below.
However, this in itself is not enough to form an image.
Having isolated the radiation from each interfering pair, the next step is to determine which part of the scattering disk the radiation has come from. This is achieved by performing Very Long Baseline Interferometry (VLBI), to observe the fluctuations in the scintillation pattern, using a number of radio telescopes separated by several thousand kilometres.
So far this ground-breaking technique has been pioneered by a collaboration of radio astronomers from the National Radio Astronomy Observatory, the University of California, the University of Massachusetts and the International Centre for Radio Astronomy Research in Western Australia. Using the Green Bank Telescope and the Arecibo Observatory, the largest steerable and non- steerable radio dishes in the world respectively, the results of these early efforts has revealed for the first time the turbulent nature of interstellar space over a large range of scales, from 1.6 billion km down to 4.5 million km (0.03 of the distance between the Earth and the Sun).
Armed with this new technique for imaging the turbulent Interstellar Medium on tiny scales, well below 1011m, the prospects for understanding the strange nature of interstellar structures is bright.

Sources:International Centre for Radio Astronomy Research

Green Laser - something to know

Many of us use the green laser as a very useful tool in star parties and in teaching newbies to learn the constellations. But there are certain things one should know about the dangers involved with this useful "toy". Here is a link which tells us how much dangerous it can be.

http://www.skyandtelescope.com/community/skyblog/observingblog/99956999.html

Let us take care to use this useful instrument safely!

Identifying Exoplanets by Their Dust Tails

Are we losing the Sahara to space? No, is the simple answer to that. The Earth has a trail of dust behind it but the dust is interstellar dust which is already present in the solar system. This interplanetary dust comes from the fragments of comets and asteroids that have collided. As the Earth travels through this dust the dust is disturbed and leaves what looks like a trail are behind it.

There is another way of looking at the formation of the dust tail. The Earth leaves behind it an area of almost suction like quality that sucks the dust in from the edges giving the appearance of a dust tail. The dust tail is pulled along by gravity and leaves a trail around the sun.

The Spitzer telescope found the dust tail a few months ago as it went straight through it. This has allowed the dust tail to be mapped and shows how the tail can give an indication of a planet. Distant exoplanets around stars many light years from our own can be indicated by strange features drawn in the dust tail by these planets. These features can be bumps, warps, rings and offsets.

The dust has already been followed in other planetary systems other than our own. About 20 dust discs have been seen and have led to a few planets already being found. One of these was found around a star called Formalhaut.

These dust tails will help the future James Webb space telescope to hunt for extra solar planets and hopefully find them quicker.