Spaceship Rosetta arrives at comet


This 4 August 2014 video is called Rosetta Probe Will Spiral In To Comet.

From the European Space Agency:

Rosetta arrives at comet destination

6 August 2014

After a decade-long journey chasing its target, ESA’s Rosetta has today become the first spacecraft to rendezvous with a comet, opening a new chapter in Solar System exploration.

Comet 67P/Churyumov–Gerasimenko and Rosetta now lie 405 million kilometres from Earth, about half way between the orbits of Jupiter and Mars, rushing towards the inner Solar System at nearly 55 000 kilometres per hour.

The comet is in an elliptical 6.5-year orbit that takes it from beyond Jupiter at its furthest point, to between the orbits of Mars and Earth at its closest to the Sun. Rosetta will accompany it for over a year as they swing around the Sun and back out towards Jupiter again.

Comets are considered to be primitive building blocks of the Solar System and may have helped to ‘seed’ Earth with water, perhaps even the ingredients for life. But many fundamental questions about these enigmatic objects remain, and through a comprehensive, in situ study of the comet, Rosetta aims to unlock the secrets within.

See also here. And here. And here. and here.

Perseid meteor shower next week


This video is called Whats Up for August Sky 2014 – Supermoon & Perseid Meteor Shower.

From eNature Blog in the USA:

Be Sure To Catch The Annual Perseid Meteor Shower Next Week

Posted on Monday, August 04, 2014 by eNature

The annual Perseid meteor shower should be visible in the night sky early next week, peaking between August 10 and August 13.

A waning Gibbous Moon (the phase following a full moon) may make it harder for observers to see the shower. Despite this, astronomers suggest that you try your luck at catching some Perseids before dawn on August 11, 12 and 13. At its peak, you can see 60 to a 100 meteors in an hour from a dark place away from the lights of civilization.

If your local weather cooperates, the best night for viewing is looking to beTuesday night— really more early Wednesday morning.

The best viewing hours should be between 11 p.m. and dawn, when the constellation Perseus is above the horizon. Although the meteors appear to come from Perseus, they actually are part of a debris trail left by Comet Swift-Tuttle, which the Earth encounters every August.

To spot meteors, find a dark-sky spot away from street lights. Perseids can appear anywhere in the sky; astronomers recommend looking in whatever direction the sky is darkest for you.

Earthsky.org has a great guide for determining the best time to catch the Perseids in your town.

Learn more about the night sky with our August Sky Guide.

Scientific American has a great overview of of the smaller meteor showers visible this month.

Spaceship approaching comet this week


This video is called CHASING A COMET – The Rosetta Mission.

From the European Space Agency:

How Rosetta arrives at a comet

1 August 2014

After travelling nearly 6.4 billion kilometres through the Solar System, ESA’s Rosetta is closing in on its target. But how does a spacecraft actually arrive at a comet?

The journey began on 2 March 2004 when Rosetta was launched on an Ariane 5 from Europe’s Spaceport in Kourou, French Guiana.

Since then, Rosetta has looped around the Sun five times, picking up speed through three gravity-assist swingbys at Earth and one at Mars, to enter an orbit similar to that of its destination: comet 67P/Churyumov–Gerasimenko.

This icy target is in an elliptical 6.5-year solar circuit that takes it from beyond the orbit of Jupiter at its furthest point, and between the orbits of Mars and Earth at its closest to the Sun.

Rosetta’s goal is to match the pace of the comet – currently some 55 000 km/h – and travel alongside it to within just 1 m/s between them, roughly equivalent to a walking pace.

Since early May, Rosetta’s controllers have been pacing it through a tightly planned series of manoeuvres designed to slow its speed with respect to the comet by about 2800 km/h, or 775 m/s, to ensure its arrival on 6 August.

ESA’s experts are playing a crucial role, having worked extensively behind the scenes to develop a series of ten orbit-correction manoeuvres that use Rosetta’s thrusters to match the spacecraft’s speed and direction with that of the comet.

“Our team is responsible for predicting and determining Rosetta’s orbit, and we work with the flight controllers to plan the thruster burns,” says Frank Dreger, Head of Flight Dynamics at ESA’s Space Operations Centre, ESOC, in Darmstadt, Germany.

The burns were carried out every two weeks in May and June and, after a short test, the three subsequent manoeuvres were some of the longest ever performed by an ESA spacecraft – exceeding seven hours.

These first burns dramatically reduced Rosetta’s speed with respect to the comet by 668 m/s of the necessary 775 m/s required by 6 August, when Rosetta will ‘arrive’ at a distance of just 100 km from the comet.

Throughout July, the burns were made on a weekly basis, and will culminate in two short orbit insertion burns set for 3 and 6 August.

Rosetta takes comet’s temperature: here.

‘Supermoon’ in North America tonight


This video is called SUPERMOON TONIGHT July 12, 2014 – The 2014 Supermoon Summer!

From eNature Blog in the USA:

Don’t Miss Tonight’s Supermoon!

Posted on Saturday, July 12, 2014 by eNature

The moon that rises tonight (Saturday) is what has come to be called a “supermoon” — only hours from being perfectly full and hours from one of the year’s closest approaches to Earth.

This combination makes the moon appear bigger and somewhat brighter than usual, even for a full moon. And because the moon always looks larger as it rises, moonrise Saturday night may show off a moon that appears about as big, bright and round as the moon can get.

As the moon rises in the southeast at Saturday evening (at 8:30 or so on the East Coast) it will move west across the dark heavens through the night and early morning before setting in the southwest on Sunday morning.

Astronomers caution that without special equipment it’s difficult for the average skywatcher to assess the moon’s brightness or size. But a supermoon last year was reported to be about 15 percent larger and 30 percent brighter than the year’s run-of-the-mill full moons, and many people may consider themselves capable of spotting a 30 percent boost in brightness.

Of course, the brightness of the moon, as seen from earth, will depend, in part, on the sky’s clarity and the amount of cloud cover. If clouds do intervene, the next supermoon is not far off. There will be one in August and another in September.

More on the supermoon at Earthsky.com.

Prehistoric meteor shower and evolution of life discovery


This video is called Late Ordovician Mass Extinction (Ordovician – Silurian).

From daily The Independent in Britain:

Scientists discover fragment of ‘missing link’ asteroid that led to explosion of life on Earth

James Vincent

Thursday 03 July 2014

Scientists in Sweden have discovered a never-before seen class of meteorite that could be the ‘missing link’ between a gigantic collision in the asteroid belt 470 million years ago and the subsequent explosion of diverse life forms here on Earth.

Although it’s usually thought that meteorite impacts are disastrous for species on Earth (the classic example is the colossal impact thought to have killed off the dinosaurs 66 million years ago) there’s plenty of evidence to suggest that these events can also be beneficial to the overall diversity on the planet.

It’s thought that just such an impact – or rather, a string of them – dramatically boosted biodiversity on the planet during the Ordovician Period some 470 million years ago. It’s believed that a collision of two asteroids (or possibly an asteroid and a comet) out in space caused a shower of meteors to rain down on Earth.

Over time fragments of this meteor shower have been found around the planet and dated to 470 million years ago – but until now scientists had not found any evidence of the ‘killer’ asteroid that started this chain of events.

During the Ordovician Period most life on Earth was found in the ocean, with jawless fish, molluscs and insect-like arthropods making up the bulk of the species roll-call. However, a study from 2008 showed that the planet went through a “major phase of biodiversification” at this time shortly after “the largest documented asteroid breakup event during the past few billion years”.

The evidence for this breakup comes from the abundance of L-chondrite meteorites – the second most common meteorite type – fragments of which first started appearing on Earth around 470 million years ago.

“Something we didn’t really know about before was flying around and crashed into the L-chondrites,” said Gary Huss, co-author of the study that analysed the sample (published in Earth and Planetary Science Letters). This newly-discovered fragment is thought to be that very object – the mysterious ‘bullet’.

The composition of the fragment differs from known meteorite samples and its exposure age – the length of time it sailed through space – places it at the ‘scene of the crime’ when meteors rained down on the planet during the Ordovician Period.

“It’s a very, very strange and unusual find,” Birger Schmitz, the lead author of the study, told Live Science. “I think [it] adds to the understanding that the meteorites that come down on Earth today may not be entirely representative of what is out there.”

It’s not clear exactly why the Ordovician meteor shower led to a greater variety of life on the plane although some more far-fetched theories suggest that life itself was ‘seeded’ by organisms hitching a ride on asteroids.

A more likely explanation is that the impact craters caused by the collisions provided perfect test-beds for developing life. When meteorites hit the surface of the planet they scooped out bubbling pools of minerals and nutrients that served – in Carl Zimmer’s words – as “natural beakers that synthesized new chemicals essential for life”. However, even this is still just a theory – and the impacts might have also fostered life by creating new habitats, like restructured shorelines.

If further geochemical tests on the newly discovered fragment confirm its suspected origins then scientists will have pinned down another piece of the solar system’s history – but figuring out what happened closer to home might be more difficult still.

Biggest rocky planet ever discovered


This video is called ‘Godzilla of Earths’ identified.

From daily The Guardian in Britain:

Monstrous rocky planet nicknamed ‘Godzilla of Earths’

The ‘mega-Earth’ Kepler-10c is the most massive rocky planet ever discovered and its surface may be cool enough for life

Ian Sample, science correspondent

Monday 2 June 2014 18.26 BST

A giant rocky planet roughly twice the size of Earth and with nearly 20 times as much mass has been spotted in orbit around a faraway star. The planet is the first to be classed as a “mega-Earth” – an alien world that dwarfs the other rocky planets known to exist outside the solar system.

Researchers cannot say whether the planet is hospitable to life, but if it has an atmosphere and clouds, the surface could be cool enough for life to survive.

In line with global rules for naming heavenly bodies, the planet goes by the official name of Kepler-10c. But Dimitar Sasselov, director of the Harvard Origins of Life Initiative, called it “the Godzilla of Earths”.

The discovery has surprised some astronomers because such large planets are thought to draw in hydrogen as they form and become gas giants, which is what happened for Neptune, Saturn and Jupiter.

“This is a planet that doesn’t fit the usual models of planetary formation,” said Xavier Dumusque at the Harvard Smithsonian Centre for Astrophysics.

Scientists reported their first glimpse of Kepler-10c in 2011 when Nasa’s Kepler space telescope watched the planet swing across the face of its parent star. But at that time, researchers knew only the size of the planet: around 30,000km wide.

Speaking at a meeting of the American Astronomical Society in Boston on Monday, Dumusque unveiled fresh measurements taken with instruments on the Italian National Galileo Telescope on La Palma in the Canary Islands. The readings showed that Kepler-10c has a mass a staggering 17 times greater than Earth.

The new measurements allowed Dumusque and others on the team to work out the average density of the new planet. The answer of 7 grams per centimetre cubed points to an alien world made of rock and water.

Kepler-10c circles a star much like our own sun about 560 light years from Earth in the northern constellation of Draco, the dragon. A year on the planet lasts 45 Earth days. The surface temperature is estimated to be a toasty 310C, but a cloudy sky could cool the planet considerably, Dumusuqe told the Guardian.

Another planet, Kepler-10b, orbits so fast and close to the same star that a new year unfolds every 20 hours.

Dumusque said that the next generation of space and ground-based telescopes will give astronomers the ability to analyse the atmospheres of planets outside the solar system. Those measurements could suggest which planets could be habitable and even inhabited.

The solar system containing Kepler-10c formed around 11bn years ago, or three billion years after the big bang that flung the universe into being.

“Finding Kepler-10c tells us that rocky planets could form much earlier than we thought. And if you can make rocks, you can make life,” said Sasselov.

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Oldest Dutch telescope, archaeological discovery


The anccient Delft telescope, photo by Marco Zwinkels

Translated from NOS TV in the Netherlands:

Oldest telescope found in Delft

Update: Wednesday, May 14, 2014, 13:05

In Delft, during excavations, recently the oldest telescope in the Netherlands was found. The technological marvel dates back to the early 17th century.

Archeologists found the device during the construction of a tunnel. After extensive research, scientists concluded that the telescope is older than a telescope by Christiaan Huygens in 1655. The viewer enlarged five times, enough to see mountains on the moon. The telescope is one of the highlights of the renovated museum the Prinsenhof, which re-opens this Friday.

The oldest telescope in the world dates back to 1609 and was by Galileo Galilei.

Unfortunately, in an interview archaeologist Steven Jongma said the telescope was probably not for astronomy, but for war; for spying on the enemy side.

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