How do we know how old Everything is?

How do we know the age of fossils, the Earth, distant stars and the Universe itself?
Fraser Cain explains in this short video.

Ποιά η αξία της έρευνας;

1.4 δισ. κόστισε η διαστημική αποστολή Ροζέτα. Μηδενικά λένε τα οφέλη για τον άνθρωπο. Αχρείαστη σπατάλη λένε.

Θα αρχίσω με τα βαρετά.

Ας δούμε τους αριθμούς.
Το συνολικό κόστος της αποστολής (1996-2015) ήταν €1.4 δισ. (κατά μέσο όρο €74.7 εκ. ετησίως).
Δηλαδή €3.2 για κάθε Ευρωπαίο φορολογούμενο (€0.2 το χρόνο απο το 1996 μέχρι το 2015).

Για να το δούμε και συγκριτικά:

• Tιμή εισιτήριου σινεμά Αθήναιον (Παρ.-Κυρ.): €7.5
• Κόστος 4 αεροπλάνων Airbus A380: €1.7 δίσ.
• Κόστος Αμερικανικών εκλογών (έτος 2012): $6.9 δίσ. (περίπου €5.0 δισ.)
• Κόστος Ολυμπιακών «Αθήνα 2004»: €8.95 δίσ.
• Κόστος δημόσιας υγείας Μ. Βρεττανίας (NHS - έτος 2012): £121.3 δίσ. (περίπου €151.8 δίσ.)
• Συνολικές εξοπλιστικές δαπάνες Ευρωπαϊκής Ένωσης (άθροισμα εθνικών δαπανών κρατών μελών - έτος 2012): €192.5 δισ.

Αλλά ποιά ήταν η αποστολή του Rosetta;
Να μελετήσει τη χημική σύνθεση ενός κομήτη, απομεινάρια απο τη δημιουργία του Ηλιακού συστήματος. Να μας δώσει πληροφορίες δηλαδή για τις συνθήκες που επικρατούσαν στο Ηλιακό σύστημα όταν αυτό ήταν στα γεννοφάσκια του. Κάποια απο τα συστατικά τέτοιων κομητών πιστεύουμε ότι έπαιξαν ρόλο στη δημιουργία των ωκεανών στη Γή - και συνεπώς στην εμφάνιση της ζωής.

Πέραν των ηλιακών συλλεκτών ρηξικέλευθης τεχνολογίας και την έμπνευση που θα αποτελέσει για τους επιστήμονες του αύριο, η αποστολή δέν έχει άμεσα και μετρήσιμα οφέλη. Όπως κάθε φιλόδοξη έρευνα που σκαλίζει μεθοδικά μέρος της ανθρώπινης άγνοιας για να αποκαλύψει κάτω απ’την κρούστα το πρόσωπο του μέλλοντος, δέ χρειάζεται να έχει.

Λέγεται ότι όταν ο πάμπτωχος Faraday είχε πλέον γίνει διάσημος, τον κάλεσε η βασίλισσα Βικτώρια για δείπνο στο παλάτι. Κάποια στιγμή τον ρώτησε ‘ …και δέ μου λέτε, σε τί μπορεί να χρησιμέψει αυτός ο “ηλεκτρισμός;”’ και της αποκρίθηκε ‘κυρία μου, σε τί χρησιμεύει ένα μωρό;’ (Κατά μιά άλλη εκδοχή η ερώτηση ήταν του πρωθυπουργού Peel, και η απάντηση ανάλογη: ‘Μα κύριε, ενδέχεται να είναι είδος φορολογήσιμο!’)

Σε τί χρησιμεύει η ανακάλυψη της φωτιάς; του τροχού; της πυρίτιδας; της Αμερικής; της ραδιενέργειας; Ότι μάζα και ενέργεια είναι ισοδύναμες; Ή η γνώση ότι η Γή είναι σφαιρική κι όχι επίπεδη και οτι δέν είμαστε το κέντρο του Σύμπαντος; Με τί μέτρα και σταθμά θα ζυγίσουμε το εκτόπισμα της νέας γνώσης και πότε θα πρέπει να γίνει η μέτρηση;

Όλες οι μεγάλες ανακαλύψεις που σε βάθος χρόνου αφήνουν ανεξίτηλα τα σημάδια τους στην ιστορία λειτουργούν ώς οδοσήματα στους δαιδαλώδεις διαδρόμους της. Δέ χρειάζεται να προσπαθούμε να τις δικαιολογήσουμε στο παρόν, γιατί δέν μπορούμε να ξέρουμε τί εγκυμονούν.

Είναι ελπιδοφόρο ότι η ανθρωπότητα ακόμα δείχνει να διαθέτει κάτι απ’ το νεανικό της σφρίγος παλεύοντας να αποκτήσει καινούριες γνώσεις αποκλειστικά και μόνο γιατί απολαμβάνει το ταξίδι. Όταν πάψουμε να επιδοτούμε την έρευνα που δέν έχει άμεσες πρακτικές εφαρμογές θα επέλθει αρτηριοσκλήρωση. Και τότε ας σφραγίσουμε τις πόρτες κι ας σβήσουμε τα φώτα.

Πηγές:
athinorama
Airbus
BBC
Το ΒΗΜΑ
Reuters
European Defence Agecy Data Portal
Office of National Statistics (UK)
European Space Agency

What is the value of basic research?

Rosetta cost €1.4 billion.
They claim there are practically no benefits. They say it was a huge waste of money.

I will start with the boring facts.

Let's take a look at the numbers.

The total cost of the mission (1996-2015) was €1.4 billion. (An average of €74.7 million p.a.). This translates to € 3.2 for every European taxpayer (€0.2 p.a. from 1996 to 2015).

For comparison:

• Price of cinema ticket (Odeon Leicester Sq): £17.5 (€21.9)
• Cost of 4 Airbus A380 airplanes: € 1.7 billion.
• Cost of US elections (year 2012): $ 6.9 billion. (about € 5.0 billion.)
• Cost of Olympic Games “Athens 2004”: € 8.95 billion.
• Public health costs in G. Britain (NHS - year 2012): £ 121.3 billion. (approximately € 151.8 billion.)
• Total EU expenditure on armaments (sum total of national expenditure of member states - year 2012): € 192.5 billion.

But what was Rosetta’s mission?
To study the chemical composition of a comet, a relic from the formation of the Solar System. To give us clues of the conditions prevailing when the solar system was at its infancy. Some components of such comets may have played a role in the formation of the oceans on Earth - and therefore the emergence of life.

Other than the innovative technology of Rosetta’s solar panels and inspiring the scientists of tomorrow, the mission has no direct and measurable benefits. Like any ambitious research that methodically chips away at human ignorance to reveal beneath the crust the face of the future, there need not be any.

It is said that when Faraday had become famous, Queen Victoria invited him for lunch at the palace. During that meal the Queen asked him “... and now pray tell me, of what use is this ‘Electricity?’ ” He reportedly replied “Madam, of what use is a new-born baby?” (In another version of the story, the question was actually posed by Prime Minister Peel, and the appropriate response was given: “Why sir, it may be a taxable item!”)

What is the use of the discovery of fire? of the wheel? of gunpowder? of America? of radioactivity? That mass and energy are equivalent? Or the knowledge that the Earth is an oblate spheroid and not flat, and that we are not the center of the Universe? By what yardstick can one measure the volume displacement of new knowledge, and when should the measurement be taken?

All major discoveries that leave indelible marks in the ageing body of History serve the purpose of road-signs for its labyrinthine pathways. There is no need to justify them in the present, because we cannot know what fruit they may yet bear. It is heartening to perceive that humanity has seemingly retained some of its youthful vigor in struggling to acquire new knowledge for the sole purpose of enjoying the journey. When we stop subsidizing research that has no immediate practical applications, arteriosclerosis will come. And then we might as well bar the doors and put the lights out.

Sources:
Odeon
Airbus
BBC
Το ΒΗΜΑ
Reuters
European Defence Agecy Data Portal
Office of National Statistics (UK)
European Space Agency

Cosmos - Episode 1 (Ελληνικοί υπότιτλοι)

The first episode of the Carl Sagan's "Cosmos" (with Greek subtitles).
To πρώτο επεισόδιο της σειράς "Cosmos" του Carl Sagan (με ελληνικούς υπότιτλους). 

Galileo Figaro Magnifico

Επιστολή του Γαλιλαίου του 1610 στην οποία αναφέρει ότι ανακάλυψε ότι ο πλανήτης Δίας περιφέρεται απο τέσσερις δορυφόρους τους οποίους ονόμασε Ιώ, Ευρώπη, Γανυμήδη και Καλλιστώ. Προς το τέλος της επιστολής έχει κάνει και ένα σχέδιο του Δία με τα τέσσερα φεγγάρια του.

Αυτή του η ανακάλυψη κατακερμάτισε την τότε επικρατούσα ιδέα οτι τα πάντα στο σύμπαν περιφέρονται γύρω απ'τη Γή. (Ολίγον τί αλλαζονική άποψη θα μου πείτε αλλα δέ βαριέσαι. 1600 ήταν αυτό, ακόμα ψήνανε μαγισσές στα κάρβουνα με πατάτες.) Το τί επακολούθησε έμεινε στην ιστορία.

Σήμερα ξέρουμε οτι ο Δίας δέν έχει μόνο τέσσερα φεγγάρια αλλά τουλάχιστον 50 και βάλε.

All alone in the night

Time-lapse footage of the Earth as seen from the International Space station. You can clearly see the lights from the cities at night, lightning storms and some beautiful aurorae.

VLT time lapse.

A clear night.

Grow and prosper with Arsenic?

New Rochelle, NY, December 7, 2010—NASA-funded research has uncovered a new life form on Earth, a microorganism that can not only survive but can thrive and reproduce by metabolizing arsenic, a chemical that is highly toxic for most other earthly organisms. This finding will revolutionize the field of astrobiology—the study of the origins, evolution, distribution, and future of life in the universe.

The new form of life, discovered in Mono Lake in California, a harsh environment with high salt, pH, and arsenic levels, represents a new strain of a common family of bacteria. It is able to substitute arsenic for phosphorus, one of the six basic building blocks of all forms of life on Earth. The microbe utilizes arsenic in place of phosphorus to build critical cell components, including its DNA, proteins, cell membranes, and energy-producing machinery.

“The discovery of a bacterium capable of substituting arsenate for phosphate in essential biomolecules impacts astrobiology in a number of ways,” says Sherry L. Cady, Professor in the Department of Geology at Portland State University. “It is quite astonishing to learn that this life form has the capacity to function in a way no other known life form can. The directed search for this biochemistry, revealed by routine methods, was essential to this find and an important lesson. Astrobiology search strategies for environments that harbor microbes with such biochemistries now increase in a way few have predicted.

However, one external researcher expressed “lingering concerns that the arsenic is simply concentrated in the bacterial cell’s extensive vacuoles and not incorporated into its biochemistry, and another said that the claim of bacteria subbing arsenic for phosphorous “is, in my opinion, not established by this work.”

The microwave sky

This image show below is a map of the whole sky as seen by the space mission Planck. This mission was launched in 2009 and is part of ESA's Cosmic Vision Programme. It is designed to image the anisotropies of the Cosmic Background Radiation (the "afterglow" of the Big Bang) over the whole sky with unprecedented accuracy.

The bright line bisecting the picture is the contribution from our own galaxy, viewed edge-on. The intense light comes from the radiation released by the interstellar dust and gas clouds.

Planck will test theories of the evolution of the universe and the origin of cosmic structure as well as provide insights into the nature of dark matter.

How do we know how far away the stars are?

This is a very common question. How would you answer it? If you are a school teacher, it is a useful excersise to ask the class to come up with ways to determine distances to nearby objects. If, on the other hand, you're too lazy to think about it, here are a couple of ways to do it.

1. For solar-system objects and relatively nearby stars, you can use the trigonometric parallax. What is parallax? For a quick demonstration, stretch out your arm, hold out your thumb upwards and close one eye. Then switch to the other eye and look at the thumb again. Even though your thumb is still, it looks like it's moving. This is because your eyes are a certain distance apart. Schematically, it looks like this:To measure the position of the star, we do the following: First, we take a photo of the area of the night sky we're interested in and measure the position of the star. Then we wait for half a year while the Earth rotates around the Sun. When the Earth is at the diametrically opposite position, we take another photo and measure the position of the star again. Because of this motion of the Earth around the Sun, stars that are too far away from us will have moved very little or not at all. But stars that are relatively close to us (up to around 40 light years) will appear to have moved more. Then, using the simple geometry shown in the diagram above, we can derive an estimate of the distance:
Distance to star = (Earth-Sun distance) / (parallax)

2. Parallax works for close-by stars, but what about really far away ones that don't seem to be moving at all? How can we get the distances to them? There are many other methods we can use and here's one of them: Main-Sequence fitting.

To explain how this method works, I'll need to introduce you to an old friend, the Hetrtzsprung-Russel diagram, shown below:

What this diagram shows is the evolution of the lives of stars. Based on many, many measurements, this is plot of the absolute brightness (also called luminosity or magnitude) of stars relative to their surface temperatures. I also need to explain the difference between absolute and apparent brightness, so let's do that first.

The light coming from a car's headlights when the car is far away will of course appear to be dimmer than if the car was closer. In other words, if you take two car headlights that are equally bright, but one is only half the distance away of the other, it will appear to be brighter. This is called apparent brightness and it is used to describe how bright a star appears to us on Earth. On the other hand, absolute birghtness is used to describe how bright the star really is.

The temperature of the star is directly related to it's colour, so Red stars are cooler than Blue stars, which have surface temperatures of tens of thousands of degrees. Astronomers measure the colour of stars by taking observations at different wavelengths (using different filters) and taking the ratio of the brightnesses. It turns out that this can be measured with great accuracy, so from that we can derive the temperature of the star, and using the information in the diagram above, we can find out the absolute brightness. Comparing this absolute brightness with the apparent brightness gives us a measure of the distance to the star. This method actually works for stars thousands of light years away!

This is by no means an exhaustive list of the methods used to determine distances to stars. To find out about some other methods, check here.

The Known Universe

Why not let your mind briefly drift away from the delays and lockdowns this Christmas period and take a flight of fancy around the known universe in this little video produced by the American Museum of Natural History.

A Universe from Nothing

An accessible and entertaining introductory talk by Laurence Krauss on the subject of Cosmology. If you're a little bit curious about how the Universe will end, watch this.

Mars as large as the Moon?

This popular urban legend is also known as Two Moons.

The brief answer is, no, Mars will not look as big as the Moon.

Every year astronomers, including the one writing this article, get this question; and every year we have to debunk it. People's memories are short while the orbit of Mars is pretty stable.

Apparently this strange hoax first surfaced on the Internet back in 2003. The relevant e-mail went something like this:

The Red Planet is about to be spectacular! This month and next, Earth is catching up with Mars in an encounter that will culminate in the closest approach between the two planets in recorded history. The next time Mars may come this close is in 2287. Due to the way Jupiter's gravity tugs on Mars and perturbs its orbit, astronomers can only be certain that Mars has not come this close to Earth in the Last 5,000 years, but it may be as long as 60,000 years before it happens again.

The encounter will culminate on August 27th when Mars comes to within 34,649,589 miles of Earth and will be (next to the moon) the brightest object in the night sky. It will attain a magnitude of -2.9 and will appear 25.11 arc seconds wide. At a modest 75-power magnification

Mars will look as large as the full moon to the naked eye. By the end of August when the two planets are closest, Mars will rise at nightfall and reach its highest point in the sky at 12:30 a.m. That's pretty convenient to see something that no human being has seen in recorded history. So, mark your calendar at the beginning of August to see Mars grow progressively brighter and brighter throughout the month. Share this with your children and grandchildren. NO ONE ALIVE TODAY WILL EVER SEE THIS AGAIN

Or the Greek version (which actually gives an incorrect year - the original doesn't):

Αυτό γίνεται μόνο μια φορά στην ζωή μας
ΔΥΟ ΦΕΓΓΑΡΙΑ ΤΑΥΤΟΧΡΟΝΑ ΣΤΟΝ ΟΥΡΑΝΟ
Την 27^η Αυγούστου 2009, 30 λεπτά μετά τα μεσάνυκτα, κοιτάξτε στον ουρανό.
Ο πλανήτης Άρης θα είναι πολύ λαμπερός μέσα στον ουρανό
Θα είναι το ίδιο μεγάλος όπως και το φεγγάρι παρόλο που ο πλανήτης Άρης θα είναι 34,65 εκατομμύρια μίλια μακριά από την Γή.
Προσπαθήστε λοιπόν να μην χάσετε αυτό το γεγονός
Θα το βλέπουμε με γυμνό μάτι σαν να και η γη έχει δύο φεγγάρια!
Η επόμενη φορά που θα λάβει χώρα αυτό το γεγονός θα είναι το έτος 2287.
Μοιραστείτε αυτή την πληροφορία με όλους τους φίλους σας γιατί κανένας ζωντανός δεν θα μπορέσει να το δει για δεύτερη φορά...

This is plainly wrong. Mars isn't going to be making a close approach on August 27. The close approach this e-mail is alluding to happened back in 2003. It did indeed get closer than it had in at least 50,000 years, but this was a very small amount. On August 27th, 2003, Mars closed to a distance of only 55,758,006 kilometers (34,646,418 miles). The Moon, by comparison, orbits the Earth at a distance of only 385,000 kilometers (240,000 miles). Mars was close, but it was still 144 times further away than the Moon. The Moon's diameter is 3474 kilometres (2159 miles), a little more than a quarter of that of the Earth while that of Mars is 6,800 km, about half that of the earth.

[Here is a little experiment you can do. Put an orange 114 meters away from you and a golf ball at your feet, lie down and look at them. Do they look about the same size?]

So what happened was this: Instead of appearing like a huge red orb in the sky, Mars looked like a bright red star. Amateur astronomers around the world set up their telescopes, and had a look at this close encounter. But you still needed a telescope and it really didn't look that much different. And everyone was happy; because if Mars did actually come close enough to rival the Moon, its gravity would alter the Earth's orbit and raise terrible tides.

See what NASA has to say about this hoax.

What is a radio image?

One of the great discoveries of the Renaissance was the theory of perspective. At the core of the theory is the realisation that a picture is a map of the directions from which light is coming as seen from a particular viewpoint. So every point on the canvas corresponds to a particular direction in space. The hue at each spot represents in colour and intensity the light arriving from the corresponding direction.

Now, colour is the eye's way of describing the spectrum of light; for instance, the colour blue tells us that the light coming from that direction contains a range of wavelengths in the visible band but is relatively strong at around 450 nm. Colour is actually a rather inaccurate measure of the spectrum; for instance, it is hard to tell a mixture of red and blue light (i.e. purple) from the very deep blue (i.e. violet). For technical work astronomers prefer to obtain a series of monochrome images through the use of coloured filters, much like the ones used in ordinary photography, so that each is a record of light with wavelengths within a specific narow band.

The astronomical B, V and R bands correspond roughly to the three basic colours, blue, green and red.
Combining the images in the different filters then allows astronomers to reconstruct a "false-colour" image of the observed object.Our images are then abstracted a futher step: the intensity of white light from our print (or computer monitor) is telling us about the insnsity of the red light on the sky.

There is no reason to restrict the wavelengths used to the tiny range that the human eye can detect. Visible light is just a tiny segment of the electromagnetic spectrum and with the appropriate technology we can make images, maps of "light" in a more general sense, at wavelengths far outside this familiar band; You are probably already familiar with such "invisible" colours like X-rays, ultraviolet, infrared and radio. In fact, the range of colours used by radio-astronomers would correspond to about twenty new colours (or bands) if we say that there are three basic ones in visible light! Fortunately, just as with monochrome images, we can use ordinary visible gray-scales to display these images of "invisible" light.

These composite images show M84, a massive elliptical galaxy in the Virgo Cluster, about 55 million light years from Earth. Radio data from the Very Large Array is shown in red. A background image from the Sloan Digital Sky Survey is shown in yellow and white.
(Credit: Radio (NSF/NRAO/VLA/ESO/R.A.Laing et al); Optical (SDSS))

The leftmost image is in radio wavelengths, the middle one in optical and the rightmost a combination of the two.

Scientists Detect "Wrong-Way" Planet

The Planetary Society
Article By Amir Alexander
August 12, 2009

An international team of scientists has detected the first extrasolar planet orbiting in the "wrong" direction. This means that the planet, designated WASP-17, is circling its star in a direction opposite to the rotation of the star itself. Such a motion, known as a "retrograde orbit," is very unusual since the motions of both star and planet were acquired from the swirling cloud of gas and dust that formed them both. As a result, the planets orbiting the same star almost always move in the same direction, which is the same as the rotation of the star itself.

A retrograde orbit is almost certainly a legacy of a planet's violent past, most likely dating to the planetary system's early days. "Newly formed solar systems can be violent places" explained graduate student David Anderson of Keele University, who is a member of the team that made the discovery. "A near-collision during the early, violent stage of this planetary system could well have caused a gravitational slingshot, flinging WASP-17 into its backwards orbit."

WASP-17 was first detected through the transit photometry technique by the Wide Area Search for Planets (WASP) consortium of British universities, using the WASP-South camera array in South Africa. But in order to detect its retrograde motion the WASP team needed an assist from planet hunters at the Geneva Observatory, who specialize in radial velocity measurements.

According to Darin Ragozzine of the Harvard-Smithsonian Center for Astrophysics astronomers can identify the direction of a planet's orbit because of slight discrepancies in the radial velocity data when a planet transits a star. Because a star is rotating, one side of it is moving towards (or away) from Earth faster than the other side. During a transit, the planet covers first one side of the star and then the other, causing a slight but measurable shift in the radial velocity readings. If during the transit the star first appears to be moving relatively slowly towards the Earth, but then faster as the transit progresses, then the planet is orbiting in the same direction as the star's rotation. But if the reverse is the case – as it is for WASP-17 – then the planet is in a retrograde orbit.

WASP-17 is located about 1000 light years from Earth, and is unusual not only because of the direction of its orbit but also because of its size and low density. Although its mass is only half that of Jupiter, its diameter is nearly twice that of our giant neighbor, which makes WASP-17 the largest known planet. The reason, according to Coel Hellier of Keele University, is related to the planet's unusual orbit. Retrograde motion coupled with a highly eccentric orbit subject the planet to intense tidal forces. Such tidal compression and stretching would have the effect of heating up the planet, causing it to expand to its current bloated dimensions. As a result, Hellier noted, the density of WASP-17 is only one seventieth (1/70) of the density of Earth.

Just as there are moons in retrograde orbits in our solar system, it stands to reason that there are also planets in retrograde orbits, and the discovery of WASP-17 did not therefore come as a complete surprise to planetary scientists. Nevertheless, this highly unusual planet does contribute to our understanding of the birth and life of planets, and adds one more member to the menagerie of strange and wonderful worlds astronomers are uncovering in the depths of space.

Ed's Teapots from Space

The Teapots from Space perfect the art of teapot abduction to find out what astronomers are and why they like astronomy, and whether they take sugar.

Herschel’s daring test: a glimpse of things to come

19 June 2009
Herschel opened its 'eyes' on 14 June and the Photoconductor Array Camera and Spectrometer obtained images of M51, ‘the whirlpool galaxy’ for a first test observation. Scientists obtained images in three colours which clearly demonstrate the superiority of Herschel, the largest infrared space telescope ever flown.

This image shows the famous ‘whirlpool galaxy’, first observed by Charles Messier in 1773, who provided the designation Messier 51 (M51). This spiral galaxy lies relatively nearby, about 35 million light-years away, in the constellation Canes Venatici. M51 was the first galaxy discovered to harbour a spiral structure.

The image is a composite of three observations taken at 70, 100 and 160 microns, taken by Herschel’s Photoconductor Array Camera and Spectrometer (PACS) on 14 and 15 June, immediately after the satellite’s cryocover was opened on 14 June.

Herschel, launched only a month ago, is still being commissioned and the first images from its instruments were planned to arrive only in a few weeks. But engineers and scientists were challenged to try to plan and execute daring test observations as part of a ‘sneak preview’ immediately after the cryocover was opened. The objective was to produce a very early image that gives a glimpse of things to come.


To the left is the best image of M51, taken by NASA’s Spitzer Space Telescope, with the Multiband Imaging Photometer for Spitzer (MIPS), juxtaposed with the Herschel observation on 14 and 15 June at 160 microns. The obvious advantage of the larger size of the telescope is clearly reflected in the much higher resolution of the image: Herschel reveals structures that cannot be discerned in the Spitzer image.



Herschel’s glimpse of M51 at 70, 100, 160 microns.

These images clearly demonstrate that the shorter the wavelength, the sharper the image — this is a very important message about the quality of Herschel’s optics, since PACS observes at Herschel’s shortest wavelengths.

Produced from the very first test observation, these images lead scientists to conclude that the optical performance of Herschel and its large telescope is so far meeting their high expectations.

Within our Galaxy, the mission’s main science objectives are:

* To study Solar System objects such as asteroids, Kuiper belt objects, and comets.
Comets are the best-preserved fossils of the early Solar System, and hold clues to the raw ingredients that formed the planets, including Earth.

* To study the process of star and planet formation.
Herschel is unique in its coverage of a wide range of infrared wavelengths, with which it will look into star-forming regions in our Galaxy, to reveal different stages of early star formation and the youngest stars in our Galaxy for the first time. The telescope will also study circumstellar material around young stars, where astronomers believe that planets are being formed, and debris discs around more mature stars.

* To study the vast reservoirs of dust and gas in our Galaxy and in other nearby galaxies.
Herschel will study in detail the physics and kinematics at work in giant clouds of gas and dust that give rise to new stars and associated planetary bodies. Herschel is also well-suited to study astrochemistry providing fundamental new insight into the complex chemistry of these molecular clouds, the wombs of future stars.

Outside our Galaxy, the mission’s main science objectives are:

* To explore the influence the galactic environment has on interstellar medium physics and star formation. Most of what we have learned about the physics and chemistry of the interstellar medium, and of the processes there such as star formation, has been gained by studies in our own Galaxy. With Herschel, we can carry out similar studies in relatively nearby galaxies as well. For example, studies of nearby low- metallicity galaxies can open the door to the understanding of these processes in the early Universe.

* To chart the rate of star formation over cosmic time. We know that star and galaxy formation commenced relatively early after the Big Bang. We also know that when the Universe was about half its current age, star formation was much more intense than it is today. Herschel is ideal to study infrared-dominated galaxies at the peak of star formation.

* To resolve the infrared cosmic background and characterise the sources. About half the energy produced and emitted throughout cosmic history now appears as a diffuse infrared cosmic background. With its large telescope, Herschel will be able to resolve the far-infrared background and characterise its constituent sources to a degree never achieved before.

(What is?) Gravitational Lensing

This is quite a rare phenomenon but occurs naturally. It happens when two astronomical bodies of extreme mass (like stars, galaxies or free-floating planets) are almost perfectly aligned as we, the observers, see them from our standpoint. What you then observe, when one star passes in front of the other, is not a dimming of the light or an eclipse, but multiple distorted images of the background star appearing in a "ring" like structure around the edge of the gravitational influence of the foreground star!



The reason that happens is because the gravity of the star that is closer to the observer bends the light rays from the further away object, acting as a kind of astrophysical "lens". This phenomenon is called gravitational lensing.



Astronomers take advantage of this rare effect to look for new exo-planets orbiting other stars.

UK radio 'superscope' gets first signals from space

A super-powerful new radio telescope network - which will allow astronomers to carry out three years worth of observations in a single day - has received its first signals from space at the University of Manchester's Jodrell Bank Observatory.

Engineers and astronomers at the famous Cheshire site have seen 'first light' with e-MERLIN, successfully processing signals from two of the telescopes in the seven-telescope network.

e-MERLIN is designed to make detailed radio images of stars and galaxies using seven telescopes spread up to 217 km apart across the UK.The radio signals collected by the telescopes are brought back to Jodrell Bank using 600 km of high-speed optical fibre cables laid by Fujitsu UK and operated by Global Crossing.



Professor Simon Garrington, Director of e-MERLIN, said:

"The new optical fibre network, together with new electronics at each telescope and a powerful new 'correlator' which combines the signals at Jodrell Bank, will make the telescope one of the most powerful of its type in the world.

"The e-MERLIN fibre network will carry as much data as the rest of the UK Internet combined, enabling astronomers to see in a single day what would have previously taken us three years of observations."

e-MERLIN is the UK's national facility for radio astronomy. Its combination of widely separated telescopes provides astronomers with a powerful "zoom lens" with which they can study details of astronomical events out towards the edge of the observable universe.

Once fully functional in early 2010, e-MERLIN's unique combination of sharpness of view and sensitivity will allow astronomers to address key questions relating to the origin and evolution of galaxies, stars and planets.

Following a call for proposals which was answered by 325 astronomers from over 100 institutes in more than 20 countries, the first major scientific legacy projects to be carried out by e-MERLIN have now been decided.

These include the study of star birth and death in our own galaxy and, looking back in time, in very distant galaxies; investigating the regions around supermassive black holes at the hearts of galaxies; tracking pulsars (the collapsed cores of exploded stars); and searching for young planets forming around nearby stars.

Dr Tom Muxlow of the University of Manchester is the lead scientist on a project to study the evolution of galaxies. He said:

"e-MERLIN will give us our first truly reliable view of the distribution of star-formation within typical galaxies at the epoch where the bulk of the stars in the present-day Universe were being formed."

The correlator (a powerful special-purpose computer) has been built by Dominion Radio Astrophysical Observatory (DRAO) in Penticton, Canada. The e-MERLIN project has benefited from close collaboration with both DRAO and the National Radio Astronomy Observatory (NRAO) in the USA, who are undertaking a similar upgrade of the Very Large Array.

e-MERLIN is funded by the Science and Technology Facilities Council (STFC), the Northwest Development Agency (NWDA), The University of Manchester, the University of Cambridge and Liverpool John Moores University.

Professor Alan Gilbert, President and Vice Chancellor of The University of Manchester said:

"This is a tremendous achievement on the part of the staff of the University's Jodrell Bank Observatory and its partners.

"e-MERLIN is a truly collaborative effort and it would not have been possible to get to this stage without funding provided by the NWDA, the STFC and our university collaborators at Cambridge and Liverpool John Moores.

"I look forward to seeing e-MERLIN taking its place as one of the world's leading astronomical facilities over the coming decade."

Professor John Womersley, Director of Science Programmes at the Science and Technology Facilities Council, said:

"This is an important first step in realising the scientific potential offered by the e-MERLIN project, which will allow us to see the radio sky in unprecedented detail.

"For the longer term, completion of e-MERLIN is an important step for UK astronomers and technologists, who are playing a significant role in future international radio astronomy facilities, including the proposed Square Kilometre Array."

Steven Broomhead, Chief Executive at the Northwest Regional Development Agency said:

"England's Northwest is widely recognised as a leading region for world-class scientific achievement, based on a talented and skilled workforce driven by innovation and enterprise.

"The e-MERLIN project is a clear demonstration of the region's expertise and will help to inspire the next generation of our scientists and engineers."

KEPLER sees first light

The centuries-old quest for other worlds like our Earth has been rejuvenated by the intense excitement and popular interest surrounding the discovery of hundreds of planets orbiting other stars. There is now clear evidence for substantial numbers of three types of exoplanets; gas giants, hot-super-Earths in short period orbits, and ice giants. The challenge now is to find terrestrial planets (i.e., those one half to twice the size of the Earth), especially those in the habitable zone→ of their stars where liquid water might exist on the surface of the planet.

The Kepler Mission is specifically designed to survey our region of the Milky Way galaxy to discover hundreds of Earth-size and smaller planets in or near the habitable zone and determine the fraction of the hundreds of billions of stars in our galaxy that might have such planets.


This image zooms into a small portion of Kepler's full field of view -- an expansive, 100-square-degree patch of sky in our Milky Way galaxy. An eight-billion-year-old cluster of stars 13,000 light-years from Earth, called NGC 6791, can be seen in the image. Clusters are families of stars that form together out of the same gas cloud. This particular cluster is called an open cluster, because the stars are loosely bound and have started to spread out from each other.

The area pictured is 0.2 percent of Kepler's full field of view, and shows hundreds of stars in the constellation Lyra. The image has been color-coded so that brighter stars appear white, and fainter stars, red. It is a 60-second exposure, taken on April 8, 2009, one day after the spacecraft's dust cover was jettisoned.

Kepler was designed to hunt for planets like Earth. The mission will spend the next three-and-a-half years staring at the same stars, looking for periodic dips in brightness. Such dips occur when planets cross in front of their stars from our point of view in the galaxy, partially blocking the starlight.

To achieve the level of precision needed to spot planets as small as Earth, Kepler's images are intentionally blurred slightly. This minimizes the number of saturated stars. Saturation, or "blooming," occurs when the brightest stars overload the individual pixels in the detectors, causing the signal to spill out into nearby pixels.

Image credit: NASA/Ames/JPL-Caltech