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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The sun’s sibling stars, astronomical lecture


New stars originating from cosmic 'clouds', 10 May 2014

On Saturday, 10 May, there was a lecture in the old astronomical observatory in Leiden, the Netherlands. Its subject was the “siblings” of the sun, the thousands of stars which formed about 4.6 billion years ago along with the sun. The photos in this blog post were made with a smartphone.

The lecturer was Professor Simon Portegies Zwart.

Baby picture of the sun's family, 10 May 2014

Stars were born and are born throughout the universe, he said. Sometimes, 100 together. Sometimes 100 million together. Usually, somewhere between 1000 and 10,000 together, as probably happened when the sun arose.

Stars, 10 May 2014

These many stars very probably have many planets; called ‘exoplanets‘, as they are outside our solar system. So far, about 1000 exoplanets are known, thanks to the Hubble telescope and other recent research. It is far easier to discover a new star than a new exoplanet; as a planet’s light, compared to a star, is like a firefly’s light near a lighthouse. At least some exoplanets have exomoons.

So, new dots in the sky get planet status. On the other hand, a solar planet recently lost planet status: Pluto. Most astronomers were in favour of changing Pluto from planet to dwarf planet. Many United States astronomers were against; probably, Professor Portegies Zwart said, because Pluto was the only planet discovered in the USA. The congress deciding on Pluto was in Prague, a relatively easy place to get the demotion of Pluto accepted.

Why did astronomers no longer want to accept Pluto as a planet? Mainly, the lecturer said, because of its eccentric and highly inclined orbit. While “real” planets go around the sun in similar orbits, close to a flat reference plane called the ecliptic, Pluto clearly differs.

Sibling star approaches sun, 10 May 2014

The eccentric orbit of Pluto may have been caused by a sibling star approaching the sun, creating chaos.

Circle of 1,6pc, 10 May 2014

This may have happened when ten stars were together within a circle of 1,6. parsec.

Andromeda galaxy, 10 May 2014

On a much bigger scale than planetary systems, there are galaxies. Like the Andromeda galaxy, with probably over a trillion stars; more than ‘our’ Milky Way, which together with Andromeda and about 50 smaller galaxies forms the Local Group. The Local Group, again, is part of the Virgin Supercluster; or Local Supercluster.

Earth's position in the universe

The lecturer showed an animation about how the sun and its sibling stars were close together shortly after their origin.

Sun in the Milky Way, 10 May 2014

Then, they started orbiting through the Milky Way. Differences in their speed, orbits, etc. made them drift further and further apart.

HD 28676, 10 May 2014

Which stars are siblings of the sun? That is not an easy question. Astronomers need complex calculations with complex computers for that. Star HD 28676 may be a good candidate. The solar sibling stars, according to recent research, are still fairly close together. “Close” in a cosmic sense, with, measured by planet Earth standards, still enormous distances between them.

Spiral, 10 May 2014

Milky Way’s Fattening Behind Revealed : DNews: here.

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New earth-like planet discovery


Kepler-186F and earth

Translated from NOS TV in the Netherlands:

Planet like Earth found

Thursday 17 April 2014, 16:00 (Update: 17-04-14, 16:19)

Astronomers have found a planet which looks like Earth. Kepler-186F is rocky, only 10 percent larger than Earth and is the right distance from its star. Scientists call it a major discovery in the search for extraterrestrial life.

The planet was found in March 2009 with the space telescope Kepler. From minor fluctuations in the light of a star, scientists infer that there is a planet circling beyond the star, they write in the scientific journal Science. In this galaxy four other planets were discovered earlier this way.

Thanks to Kepler in this way a total of almost 2000 exoplanets have been discovered. That also included earth-like planets, but none of them looks so much like our earth as Kepler-186F.

Goldilocks zone

The distance of the planet from the star is just right to make liquid water possible. The planet is on the edge of the so-called Goldilocks zone. Like in the fairy tale of the three bears, it is not so hot there that water evaporates and not so cold that it freezes.

Whether anything actually lives on the planet, astronomers cannot say. The star around which the planet orbits may be a spoilsport.

For Kepler-186F orbits around a different kind of star than our sun, being a red dwarf. Such a star is smaller than our sun, but also more active. This might expose the planet to too much radiation to make life possible.

More time

The chances of life are improved on the other hand by dwarf stars living longer than their larger counterparts. This would give more time to develop life. Also maybe on the planet there is an atmosphere filtering the radiation.

The planet is 500 light years away from our solar system in the constellation Cygnus. It turns around its star once every 130 days.

Most Earth-like planet yet discovered: here.

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Total lunar eclipse in North America


This video from the USA is called NASA – Skywatchers’ Delight – Multiple Lunar Eclipses expected in April 2014.

From eNature Blog in the USA:

Watch The Moon Disappear Before Your Eyes—Don’t Miss Tonight’s Total Lunar Eclipse!

Posted on Monday, April 14, 2014 by eNature

There’s a total lunar eclipse happening across all of North America LATE tonight and early tomorow morning (the 15th). A total lunar eclipse occurs when the full Moon passes through the dark inner core of the Earth’s shadow, which is called the umbra.

North America hasn’t experienced a total eclipse of the Moon since 2011. But that dearth ends in the early morning hours of April 15th (or late on April 14th for the West Coast), when the full Moon passes through the umbra and all but disappears. In fact, we’re due to see three more eclipses over the next two years, a bounty of lunar eclipses that won’t occur again until 2032.

While it may be happening a little late for folks on the East Coast, you’ll find that a total eclipse is worth staying up for.

The eclipse will start to be noticeable around 1:00 AM ET when the Moon’s leading edge enters Earth’s penumbra, the outer portion of its shadow.

Initially the affect is not especially noticeable — you won’t start to see a dusky fringe along the Moon’s leading edge (known to astronomers as its “celestial east”) until the the moon intrudes about halfway across the penumbra. As the Moon glides deeper into the penumbra and approaches the umbra, the shading effect of the Earth’s shadow on the appearance of the moon becomes much more obvious.

The total eclipse begins at 3:07 AM ET when the moon is completely within the Earth’s shadow. From the Moon’s perspective, the Sun remains completely hidden for 1 hour 18 minutes. From Earth’s perspective, the lunar disk isn’t completely blacked out but instead remains dimly lit by a deep orange or red glow— but it’s easy to think the moon’s completely missing if you don’t look closely.

You can do the math and see the timing is a little more friendly for folks on the west coast.

Regardless of how late the hour, you’ll not regret staying up to catch one of nature’s best shows!

Sky and Telescope magazine provided much of the info in this entry and has LOTS more great detail about the eclipse.

‘Blood Moon’ Eclipse: Best Pictures Of Amazing Sight Above America: here.

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