13 Jun 2017

Jupiter is the most ancient Planet in The Sun’s family

Jupiter_and_its_shrunken_Great_Red_SpotJupiter formed in a geologic blink. Its rocky core coalesced less than a million years after the beginning of our Solar System, scientists reported Monday in the Proceedings of the National Academy of Sciences. Within another 2 or 3 million years, that core grew to 50 times the mass of Earth.

Scientists have previously built computer models of the birth of Jupiter. But this study "is the first time that we can say something about Jupiter based on measurements done in the lab," said study co-author Thomas Kruijer, a researcher at the Lawrence Livermore National Laboratory in California.

To probe the planet's creation, experts sampled extra-terrestrial material that happens to land on Earth - ancient meteorites.

Our Solar System began as a disk of dust and gas 4.6 billion years ago. Of the planets, first came the gas giants, followed by such rock-and-metal terrestrial worlds as Earth. Jupiter is the biggest of the brood.

Despite being mostly gas by bulk, it's more than 300 times the mass of Earth. For that reason astronomers suspect the planet was the oldest, able to scoop up more material out of the disk before its younger siblings appeared.

The new study supports the idea of a firstborn Jupiter. When Jupiter formed, the growing planet swept up a great swath of gas and dust as it circled the sun.

What's more, it acted as a barrier to shield the inner Solar System from wayward meteorites. When the Solar System was about 1 million years old, Jupiter's gravity was strong enough to prevent rocks from crossing beyond its orbit, like a club bouncer who forces latecomers to wait on the sidewalk.

"At about 1 million years, you have Jupiter getting big enough to cut off the inner Solar System from the outer Solar System," said Brown University's Brandon Johnson, a planetary scientist who was not involved with the new research.


Then, when the Solar System was around 4 million years old, Jupiter grew to about 50 Earth masses and headed toward the sun. This lowered the bouncer's velvet rope, allowing the outer asteroids to mix with the inner rocks.

Today, they're jumbled together in a single belt, which exists between Jupiter and Mars. Rocks from this mixture land on Earth, where scientists such as Kruijer can study them.

The new study adds evidence to the idea that Jupiter temporarily split the population of meteorites in the Solar System in two: those between Jupiter and the Sun, and those beyond Jupiter.

If a pair of inner and outer space rocks landed in your front yard, and you picked them up after they cooled down and the dust settled, you wouldn't be able to spot a difference.

But Kruijer and his colleagues can measure specific chemical signatures in meteorites - which reveal not only the rocks' age but which of the two groups they once belonged to.

It was only recently that technological advances allowed scientists to measure the differences in the two, Kruijer said.

The meteorite groups separated around 1 million years after the Solar System formed, and stayed apart until about 4 million years post-formation, according to the new analysis. Crucially, the two populations existed simultaneously for a few million years.

"It cannot be a temporal change. It must be a spatial separation," Kruijer said.

Something must have kept them apart. The most likely culprit, the authors of the study say, is a young Jupiter. "It's hard to think of any other possibility," he said.

"This is interesting work and presents an interesting result, which conforms well with our existing understanding," said Konstantin Batygin, a planetary astrophysicist at the California Institute of Technology who was not involved with the research. "It may very well be what had happened."

Planetary scientists are like detectives, Batygin said, scouring a scene for hints about what transpired.

"In a crime scene it's the little splatters of blood on the ceiling," he said, "that will tell you more than the dismembered limbs."

In this analogy the planets are the chopped limbs and the meteorites the bloody spray. But, as with hunting for murder clues, he added, "there's always room for doubt with these types of problems."

It might be that the structure of the early disk kept the meteorite groups isolated, said Kevin Walsh, an astronomer at Southwest Research Institute in Colorado who was not involved with this work.

"The key point the authors make is that Jupiter must form to keep these asteroid reservoirs separate while they form," he said in an email.

"It is possible that we have a naïve understanding of the way asteroid building blocks could move in an early Solar System, and that a Jupiter mass planet isn't necessary."

But such an early Jupiter jibes with other ideas about the early Solar System.


One concept, called the grand tack hypothesis, casts Jupiter as a wanderer. In the grand tack hypothesis, first proposed by Walsh and other scientists in 2011, Jupiter began to barrel toward the centre of the Solar System.

That was, until Saturn formed, pulling Jupiter backward. This pendulous wrecking-ball motion could be responsible for, among other things, the mixing of the meteorite groups into one belt.

And it's likely that this young and massive Jupiter is responsible for a small Earth with a thin atmosphere. "We occupy a somewhat strange world, galactically speaking," Batygin said.

Earth, which formed about 100 million years after the solar nebula, lacked the gravity for a thick "nasty hydrogen helium atmosphere" found on other worlds.

Thank Jupiter for sucking up most of that material.

Exoplanet hunters looking at other star systems have found several super-Earths, planets larger than Earth but smaller than gas giants like Neptune. Few exoplanets are as small as two Earths and exist in the habitable zone of their star.

Kruijer speculated that the young Jupiter is the reason our Solar System does not have any super-Earths close to our star.

In this light Jupiter is a pillar of the Solar System. "Even in its infancy, Jupiter really controlled the dynamics and evolution of the Solar System," Johnson said.

"It's the biggest thing there is. Even at a million years it's changing the way that our Solar System looked."

12 Jun 2017

On This day 13 June 2017

mars jup sat

Please click on the images to enlarge


Comet C/2015 V2 Johnson is at perihelion today at a distance of just over 152 million miles from the Sun. The ‘green’ comet is visible in a pair of 10x50 binoculars, and can be found in the constellation of Bootes, before moving south into Virgo on 15 June. RA 14h 24m 24.8s DEC +07 13’ 27”.

Today THE MOON lies in the constellation of Sagittarius RA 20h 57m33s Dec -15 56’ 55” Lunation 19.21 days, illuminated 82.6% Libration, Position Angle -17.8° Latitude -00° 42’ in Longitude -05h 56m.

Today MERCURY is visible in the morning RA 04h 50m 28.7s Dec +22° 18’ 35” Mag -2.0 Diameter 5.28” Phase 0.930

Today Venus (Mag ‒4.4) is also visible in the morning sky. RA 2h 24m 47.8s Dec +11° 35’ 04” Diameter 20.84” Phase 0.56.

Today MARS (Mag +1.7) lies in the constellation Gemini close to the open cluster M35 RA 06h 27m 05.7” Dec +24° 13’ 45” Diameter 3.8”. The planet is visible in the west after sunset.

The Asteroid CERES was in conjunction with the Sun on 6 June

Juno (Mag +10) Constellation Scutum RA 18h 50m 11s Dec –04 52’ 21”

ashampoo_snap_2017.06Today Jupiter (Mag‒2.2) lies in the constellation of Virgo with the nice double star Gamma-Virginis --- Porrima --- to the upper right. RA 12h 50m 53.9s Dec -03° 57’ 19” Diameter 39.9.”  The longitude of the Great Red Spot is 270 degrees (System II) and will be visible on these dates.

Today Saturn (Mag 0.0) lies in the constellation of Ophiuchus RA 17h 36m 45.5s Dec -21° 58’ 16” Diameter 18.38”

Today Uranus (Mag +5.9) lies close to the star Omicron Piscium RA 01h 43m 04s Dec+10° 03’ 56.2”

Today Neptune (Mag +7.9) lies in the constellation Aquarius (Transit 05h 40m UT) RA 23h 03m 24” Dec -07 01’ 20.4”

10 Jun 2017


Comet Johnson chartAll times are given in UT ‘Universal Time’

Comet C/2015 V2 Johnson is visible in a pair of 10x50 binoculars, and can be found in the constellation of Bootes, and moves south into Virgo on 15 June.

RA 14h 26m 42.2s

DEC +07 13’ 21”.

In addition, comet 289/P Blanpain Mag +20 is at opposition. It lies in the constellation of Ophiuchus just below the planet Saturn.

The Asteroid 1674 Groeneveld (Mag 16.9) Occults the 6.4 Mag star HIP 42516 which can be seen by amateur astronomers in Brazil and Peru. RA 08h 40m Dec -20° 00’ 27.6”

The Apollo class Asteroid 2017 KF3 (Mag 21) flies by the Earth at a distance of about 3 million miles. The Amor class Asteroid 397 Vienna (1894 BM) also flies by the Earth today at a distance of 161,650 million miles.

Today THE MOON lies in the constellation of Sagittarius RA 19h 16m35s Dec -19 06’ 55” Lunation 17.21 days, and is at minimum Libration (Size 5.5°) Position Angle 128° Latitude -03° 14’  Longitude –03 50’.


Today Mercury is visible in the morning sky 5° north of Aldebaran RA 04h 33m 04.2s Dec +21° 23’ 41” Mag -2.0 Diameter 5.38” Phase 0.893

Today Venus is at Aphelion. The planet (Mag -4.4) is also visible in the morning sky. RA 2h 16m 54.7s Dec +10° 58’ 10” Diameter 21.71” Phase 0.540.

Today Mars (Mag +1.7) lies in the constellation Gemini close to the open cluster M35 RA 06h 21m 18.2” Dec +24° 16’ 28” Diameter 3.65”. The planet is visible in the west after sunset.

The Asteroid Ceres was in conjunction with the Sun on 6 June

The Asteroid Juno (Mag +10) lies in the Constellation Scutum RA 18h 57m 16s Dec –04 54’ 11”

Today Jupiter (Mag‒2.2) lies in the constellation of Virgo with the nice double star Gamma-Virginis --- Porrima --- to the upper right. RA 12h 50m 50.2s Dec -03° 56’ 21” Diameter 39.9”

Today Saturn (Mag 0.0) lies in the constellation of Ophiuchus RA 17h 37m 23.6s Dec -21° 58’ 29” Diameter 18.38”

Today Uranus (Mag +5.9) lies close to the star Omicron Piscium RA 01h 42m 47s Dec+10° 02’ 19.3”

Today Neptune (Mag +7.9) lies in the constellation Aquarius (Transit 05h 40m) RA 23h 03m 23.7” Dec -07 01’ 21.3”

8 Jun 2017

Killer Asteroid on Earth Collision Course May Lurk Among Shooting Stars

1032242493One of the largest and most famous annual meteor showers may have taken a sinister turn, as the risk of the shower heralding a large asteroid on a track to smash into Earth and cause untold devastation has become more and more significant, according to Czech astronomers.

The Astronomical Institute of the Czech Academy of Sciences came to their grim conclusions after observing the Taurid meteor shower, which appears twice a year in the night sky: once during the early summer and once around Halloween.

A meteor shower occurs when Earth's movements send it through a stream of cosmic debris. Typically, the meteoroids that would hit Earth either disintegrate or are shrunken to a tiny size by Earth's atmosphere.

"We performed careful analysis of 144 Taurid fireballs observed by new digital autonomous fireball observatories of the European Fireball Network displaced over Czech Republic at 13 stations, Austria and Slovakia in 2015, when the activity was enhanced," researchers said.

The brightest fireball studied "was caused by a body in excess of 1,000 kg (2,204 lb), which corresponds to diameter more than one meter. Based on orbital similarity, we argue that asteroids of several hundred meters in diameter are members of the Taurid new branch as well."

The good news is that the larger asteroids seem to be porous and fragile, meaning they're more likely to split apart and subsequently disintegrate when they enter Earth's atmosphere. However, there's no guarantee that will happen.

Many of the Taurids come from Encke, a comet that orbits the sun and has been slowly crumbling over the last 30,000 years. Some astronomers have suggested that the Tunguska event, when a 500-foot asteroid exploded a few miles off the ground and flattened 770 square miles of Siberian wilderness in 1908, was caused by a fragment of Encke. The explosion was comparable to that of a 20-megaton nuclear bomb and would have been cataclysmic had it hit a densely populated area.

7 Jun 2017

Scientists just did something even Einstein didn’t think was possible

albert_einstein_by_zuzahin-d5pcbugResearchers just confirmed a theory originally proposed by Albert Einstein nearly a century ago, and it’s something that even the famed physicist thought was impossible. A team of scientists led by Kailash Sahu has observed a gravitational phenomenon in which light from stars is bent as it makes its way past neighbouring stars, and will publish their report in the journal Science on June 9th. 

Einstein’s idea — that the gravitational pull of stars can actually manipulate light passing by from extreme distances — is commonly called “gravitational micro lensing.” The famous scientist never actually observed the effect, and had no proof that it indeed existed, but his knowledge of the effects of gravity told him it was not only possible, but likely. In 1936, he wrote in Science that, because of the distance between stars, “there is no hope of observing this phenomenon directly.”

Now, modern technology makes such an observation possible, and researchers have just confirmed that Einstein was indeed correct. That isn’t to say there was any doubt — examples of gravitation micro lensing have been detected in space before, but never in this context, as Einstein predicted, and never studied and measured in this way.

“When a star in the foreground passes exactly between us and a background star, gravitational micro lensing results in a perfectly circular ring of light – a so-called ‘Einstein ring.'” said Terry Oswalt, astronomer with Embry-Riddle Aeronautical University and chair of the Department of Physical Sciences. “The ring and its brightening were too small to be measured, but its asymmetry caused the distant star to appear off-centre from its true position,” Oswalt says. “This part of Einstein’s prediction is called ‘astrometric lensing’ and Sahu’s team was the first to observe it in a star other than the Sun.”

So what would Einstein think of this? “Einstein would be proud,” Oswalt said. “One of his key predictions has passed a very rigorous observational test.”

6 Jun 2017

Celestial boondocks: Study supports the idea we live in a void

142350_webAUSTIN, Texas -- Cosmologically speaking, the Milky Way and its immediate neighbourhood are in the boondocks.

In a 2013 observational study, University of Wisconsin-Madison astronomer Amy Barger and her then-student Ryan Keenan showed that our galaxy, in the context of the large-scale structure of the universe, resides in an enormous void -- a region of space containing far fewer galaxies, stars and planets than expected.

Now, a new study by a UW-Madison undergraduate, also a student of Barger's, not only firms up the idea that we exist in one of the holes of the Swiss cheese structure of the cosmos, but helps ease the apparent disagreement or tension between different measurements of the Hubble Constant, the unit cosmologists use to describe the rate at which the universe is expanding today.

Results from the new study were presented here today (June 6, 2017) at a meeting of the American Astronomical Society.

The tension arises from the realization that different techniques astrophysicists employ to measure how fast the universe is expanding give different results. "No matter what technique you use, you should get the same value for the expansion rate of the universe today," explains Ben Hoscheit, the Wisconsin student presenting his analysis of the apparently much larger than average void that our galaxy resides in. "Fortunately, living in a void helps resolve this tension."

The reason for that is that a void -- with far more matter outside the void exerting a slightly larger gravitational pull -- will affect the Hubble Constant value one measures from a technique that uses relatively nearby supernovae, while it will have no effect on the value derived from a technique that uses the cosmic microwave background (CMB), the leftover light from the Big Bang.

The new Wisconsin report is part of the much bigger effort to better understand the large-scale structure of the universe. The structure of the cosmos is Swiss cheese-like in the sense that it is composed of "normal matter" in the form of voids and filaments. The filaments are made up of super clusters and clusters of galaxies, which in turn are composed of stars, gas, dust and planets. Dark matter and dark energy, which cannot yet be directly observed, are believed to comprise approximately 95 percent of the contents of the universe.

SuperclusterThe void that contains the Milky Way, known as the KBC void for Keenan, Barger and the University of Hawaii's Lennox Cowie, is at least seven times as large as the average, with a radius measuring roughly 1 billion light years. To date, it is the largest void known to science. Hoscheit's new analysis, according to Barger, shows that Keenan's first estimations of the KBC void, which is shaped like a sphere with a shell of increasing thickness made up of galaxies, stars and other matter, are not ruled out by other observational constraints.

"It is often really hard to find consistent solutions between many different observations," says Barger, an observational cosmologist who also holds an affiliate graduate appointment at the University of Hawaii's Department of Physics and Astronomy. "What Ben has shown is that the density profile that Keenan measured is consistent with cosmological observables. One always wants to find consistency, or else there is a problem somewhere that needs to be resolved."

The bright light from a supernova explosion, where the distance to the galaxy that hosts the supernova is well established, is the "candle" of choice for astronomers measuring the accelerated expansion of the universe. Because those objects are relatively close to the Milky Way and because no matter where they explode in the observable universe, they do so with the same amount of energy, it provides a way to measure the Hubble Constant.

Alternatively, the cosmic microwave background is a way to probe the very early universe. "Photons from the CMB encode a baby picture of the very early universe," explains Hoscheit. "They show us that at that stage, the universe was surprisingly homogeneous. It was a hot, dense soup of photons, electrons and protons, showing only minute temperature differences across the sky. But, in fact, those tiny temperature differences are exactly what allow us to infer the Hubble Constant through this cosmic technique."

A direct comparison can thus be made, Hoscheit says, between the 'cosmic' determination of the Hubble Constant and the 'local' determination derived from observations of light from relatively nearby supernovae.

The new analysis made by Hoscheit, says Barger, shows that there are no current observational obstacles to the conclusion that the Milky Way resides in a very large void. As a bonus, she adds, the presence of the void can also resolve some of the discrepancies between techniques used to clock how fast the universe is expanding.

5 Jun 2017

Aliens … No … Famous ‘WOW’ signal was caused by two comets

Ashampoo_Snap_2017.06.05_21h02m44s_001_On 15 August 1977, the Ohio State University Radio Observatory detected a strong narrowband signal in the constellation Sagittarius (Sgr). The frequency of the signal, which matched  closely with the hydrogen line (1420.40575177 MHz), peaked at approximately 23:16:01 EDT. The signal was so strong that astronomer Jerry Ehman, who first spotted it, circled it in red pen and wrote "Wow!" in the margin. The "Wow! signal," as it would come to be known, became the best evidence ever obtained for extra-terrestrial life.At least, until now. One astronomer believes he's figured out what really caused the Wow! signal and—spoiler alert—it's not aliens.

On  the same date and time, comet 266P/Christensen was transiting in the vicinity where the “Wow!”

Signal was detected. The purpose of this investigation, therefore, was to collect and analyse  radio emission spectra and determine if comet 266P/Christensen and/or any other previously unknown  celestial body in the Solar System was the source of the 1977 “Wow!” Signal. This investigation, moreover, was designed to improve our understanding of the content and origin of the “Wow!’ Signal by determining if a neutral hydrogen cloud emitted from a short-period comet could be detected by a terrestrial radio telescope.



Astronomer Antonio Paris has been studying the Wow! signal for a long time. In 2016, he released a paper along with fellow astronomer Evan Davies suggesting that the signal could have been caused by a comet orbiting in the inner solar system. Specifically, the 2016 paper identified two comets, 266P/Christensen and P/2008 Y2 (Gibbs), that were both in the area where the Wow! signal was detected.

Both of these comets have large hydrogen clouds surrounding them that could produce the kind of signal detected in 1977. Paris spent about four months in late 2016 and early 2017 with a telescope pointed at comet 266P, and found strong signals of the same type as the Wow! signal.

Paris also examined several other similar comets and found the same type of hydrogen cloud and the same type of signal, which means that even if comet 266P wasn't the specific source of the Wow! signal, another comet is most likely the culprit.

This is bad news for anyone holding out hope that the Wow! signal would be aliens, but it's a solid conclusion to one of the biggest mysteries in astronomy. Now that we know comets can create these otherworldly signals, any future signals we get will have to be vetted much more carefully.