## Sci-Advent – New superhighway system discovered in the Solar System

Researchers have discovered a new superhighway network to travel through the Solar System much faster than was previously possible. Such routes can drive comets and asteroids near Jupiter to Neptune’s distance in under a decade and to 100 astronomical units in less than a century. They could be used to send spacecraft to the far reaches of our planetary system relatively fast, and to monitor and understand near-Earth objects that might collide with our planet.

The arches of chaos in the Solar System. Science Advances, 2020; 6 (48): eabd1313 DOI: 10.1126/sciadv.abd1313

In their paper, published in the Nov. 25 issue of Science Advances, the researchers observed the dynamical structure of these routes, forming a connected series of arches inside what’s known as space manifolds that extend from the asteroid belt to Uranus and beyond. This newly discovered “celestial autobahn” or “celestial highway” acts over several decades, as opposed to the hundreds of thousands or millions of years that usually characterize Solar System dynamics.

The most conspicuous arch structures are linked to Jupiter and the strong gravitational forces it exerts. The population of Jupiter-family comets (comets having orbital periods of 20 years) as well as small-size solar system bodies known as Centaurs, are controlled by such manifolds on unprecedented time scales. Some of these bodies will end up colliding with Jupiter or being ejected from the Solar System.

The structures were resolved by gathering numerical data about millions of orbits in our Solar System and computing how these orbits fit within already-known space manifolds. The results need to be studied further, both to determine how they could be used by spacecraft, or how such manifolds behave in the vicinity of the Earth, controlling the asteroid and meteorite encounters, as well as the growing population of artificial human-made objects in the Earth-Moon system.

## Comet 45P Returns

Comet 45P Returns
An old comet has returned to the inner Solar System. Not only is Comet 45P/Honda–Mrkos–Pajdušáková physically ancient, it was first discovered 13 orbits ago in 1948. Comet 45P spends most of its time out near the orbit of Jupiter and last neared the Sun in 2011. Over the past few months, however, Comet 45P‘s new sunward plummet has brightened it considerably. Two days ago, the comet passed the closest part of its orbit to the Sun. The comet is currently visible with binoculars over the western horizon just after sunset, not far from the much brighter planet Venus. Pictured, Comet 45P was captured last week sporting a long ion tail with impressive structure. Comet 45P will pass relatively close to the Earth early next month.

## Shell Game in the LMC

Shell Game in the LMC

An alluring sight in southern skies, the Large Magellanic Cloud (LMC) is seen here through narrowband filters. The filters are designed to transmit only light emitted by ionized sulfur, hydrogen, and oxygen atoms. Ionized by energetic starlight, the atoms emit their characteristic light as electrons are recaptured and the atom transitions to a lower energy state. As a result, this false color image of the LMC seems covered with shell-shaped clouds of ionized gas surrounding massive, young stars. Sculpted by the strong stellar winds and ultraviolet radiation, the glowing clouds, dominated by emission from hydrogen, are known as H II (ionized hydrogen) regions. Itself composed of many overlapping shells, the Tarantula Nebula is the large star forming region at top center. A satellite of o ur Milky Way Galaxy, the LMC is about 15,000 light-years across and lies a mere 180,000 light-years away in the constellation Dorado.

## Rosetta’s Farewell

Rosetta’s Farewell
After closely following comet 67P/Churyumov-Gerasimenko for 786 days as it rounded the Sun, the Rosetta spacecraft’s controlled impact with the comet’s surface was confirmed by the loss of signal from the spacecraft on September 30, 2016. One the images taken during its final descent, this high resolution view looks across the comet’s stark landscape. The scene spans just over 600 meters (2,000 feet), captured when Rosetta was about 16 kilometers from the comet’s surface. Rosetta’s descent to the comet brought to an end the operational phase of an inspirational mission of space exploration. Rosetta deployed a lander to the surface of one of the Solar System’s most primordial worlds and witnessed first hand how a comet changes when subject to the increasing intensity of the Sun’s radiation. The decision to end the mission on the surface is a result of the comet’s orbit now taking it to the dim reaches beyond Jupiter where there would be a lack of power to operate the spacecraft. Mission operators also faced an approaching period where the Sun would be close to line-of-sight between Earth and Rosetta, making radio communications increasingly difficult.

## Quantum Tunnel answers: Solar flares

I am very pleased that the first (of many I hope) questions has arrived to the mailbox of the Quantum Tunnel blog. So here we go:

Dear Quantum Tunnel:

Is it true that there will be a solar storm in December (2014) and there will be three days of darkness? If so, why is this happening?

Yours sincerely,

Pablo Mitlanian

Well, thanks a lot for your question Pablo. Let me first start by clearing the air and respond directly to the question: No, it is not true that there will be a solar storm that will cause three days of darkness. So there you go! I think this is a rumor that has been going around the interwebs for quite some time. Neither NASA nor any other respected scientific institution has made such a claim.

Now, let us address the actual facts related to the question: solar storms do indeed exist and they usually refer to sudden release of energy from the surface of the Sun, we are talking about $6times 10^{25}$ Joules. To put this in perspective, the impact in Chicxulub (Mexico) that caused the mass extinction of the dinosaurs is around $1times 10^8$ Joules. Solar flares are sometimes followed by the ejection of plasma from the upper atmosphere of the Sun (called solar wind) and accompanying magnetic fields. The particles that make up the solar wind (electrons, ions and atoms) reach the Earth one or two days after the event. Incidentally, the charged particles hitting the magnetosphere are the reason for beautiful auroras!

As you can imagine, solar flares have a definite impact on space weather locally, and thus on the Earth too. The particles from the solar wind can impact with the Earths magnetosphere and present some hazard to spacecraft and satellites and in some cases affect the terrestrial electric power grids. One of the most powerful solar flares observed was recorded in 1859 by Richard Carrington and, independently, Richard Hodgson and the auroras could be seen even in Cuba and Hawaii!

The Sun’s magnetic activity has been observed to follow a periodic cycle of about 11 years and on a maximum there are more solar flares. The last maximum was in 2000 and we were thus expecting a maximum around 2011, but as with other weather (terrestrial or not) predictions, there is a margin of error. So, I am sure you can go around doing your end of year celebrations without worrying about solar flares and who knows you may even have a chance to see a charming aurora!

If you want to ask a question to Quantum Tunnel use the form here.

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‘Extreme solar storm’ could have pulled the plug on Earth – The Guardian

## Saturn’s Hexagonal Storm – Sci-advent – Day 17

Saturn is well-know by its rings and it cannot be denied that they are a feature that makes of this planet an intriguing world. However, in the 1980s NASA’s Voyager 1 and 2 observed a bizarre, but symmetrically interesting feature in the north pole of Saturn: a hexagonal shaped storm. More recently, NASA’s Cassini has been able to image Saturn hexagon in greater detail. The hexagon is 25,000 km (15,000 miles) across. In fact, you could nearly fit four Earth-sized planets there.

The hexagon appears to have remained fixed with Saturn’s rotation rate and axis since first glimpsed by Voyager. The actual reason for the pattern in the storm is still a matter of speculation. Kevin Baines, atmospheric expert and member of Cassini’s visual and infrared mapping spectrometer team at NASA’s Jet Propulsion Laboratory is quoted saying: “Once we understand its dynamical nature, this long-lived, deep-seated polar hexagon may give us a clue to the true rotation rate of the deep atmosphere and perhaps the interior.

## Sir Patrick Moore – Sci-advent – Day 8

British astronomer and broadcaster Sir Patrick Moore, died aged 89

Sir Patrick Moore was an inspiration to generations of astronomers and scientists in general. He presented the BBC programme The Sky At Night for over 50 years, making him the longest-running host of the same television show ever. The first programme was on April 24th, 1957. Sir Patrick’s last appearance was last Monday, December 3rd, 2012.
He wrote dozens of books on astronomy and his research was used by the US and the Russians in their space programmes.

## Winter Solstice Lunar Eclipse

William Castleman shot an amazing time lapse video of last night’s Winter Solstice Lunar Eclipse on the darkest day in 372 years. It was shot from Gainesville, Florida from 1:10 AM EST (6:10 GMT) to 5:03 AM EST (10:03 GMT).