Space Sunday: Jupiter, exoplanets, Opportunity, and Wow! again

The planets – actual size. Jupiter is the biggest – and most likely the oldest – of our solar system’s family of gas and solid body planets. Credit: NASA

Jupiter is the most massive planet of the solar system and its presence had an immense effect on the dynamics of the solar accretion disk (the disk of dust and stellar material which surrounded and formed the Sun). Knowing the age of Jupiter is key for understanding how the solar system evolved toward its present-day architecture. Although models predict that Jupiter formed relatively early in the solar system’s history, until now, its formation has never been dated. Now, an international study suggests it was the very first planet to form.

The team, comprising scientists from the US Lawrence Livermore National Laboratory and Germany’s Institut für Planetologie at the University of Münster, believe that Jupiter’s core started forming within the first million years of the solar system’s existence. By looking at tungsten and molybdenum isotopes on iron meteorites, the team found that meteorites are made up from two genetically distinct nebular reservoirs that coexisted but remained separated between 1 million and 3-4 million years after the solar system formed.

“The most plausible mechanism for this efficient separation is the formation of Jupiter, opening a gap in the accretion disk, preventing the exchange of material between the two reservoirs,” said Thomas Kruijer, lead author of team’s paper, published in the June 12th Proceedings of the National Academy of Sciences.

“We do not have any samples from Jupiter (in contrast to other bodies like the Earth, Mars, the moon and asteroids),” he continued, when discussing the paper. “In our study, we use isotope signatures of meteorites (which are derived from asteroids) to infer Jupiter’s age. Jupiter is the oldest planet of the solar system, and its solid core formed well before the solar nebula gas dissipated, consistent with the core accretion model for giant planet formation.”

Even now, Jupiter sucks up material falling towards the Sun from further out in the solar system. This August 2009 image shows the result of an object striking the upper reaches of Jupiter’s southern hemisphere (south is at the top in the photo). The object was most likely a comet or asteroid a few hundred metres across. Credit: NASA

The team showed through isotope analyses of meteorites that Jupiter’s solid core formed within only about 1 million years after the start of the solar system history, rapidly growing to a mass of around 20 times that of Earth, then expanding more gradually to around 50 Earth masses over the next 2-3 million years. This rapid formation meant Jupiter acted as a barrier against inward transport of material from the outer reservoir of nebula material to the inner one, potentially explaining why our solar system lacks any super-Earths (a solid planet with a mass and size greater than Earth’s) orbiting the sun – Jupiter effectively vacuumed up the material.

The common belief among planetary scientists has leaned towards the gas giants of the outer solar system having formed relatively early in the solar system’s history, before the complete dissipation of the solar nebula—the gaseous circumstellar disk surrounding the young Sun – which occurred around 10 million years after the solar system formed. These finding fully support that belief, but has been able to far more precisely pin-down Jupiter’s birth date.

“Our measurements show that the growth of Jupiter can be dated using the distinct genetic heritage and formation times of meteorites,” Kruijer said.

Chinese Resupply Vehicle Competes 2nd Lab Refuelling

China’s automated Tianzhou-1 re-supply vehicle has carried out a successful second rendezvous with the currently uncrewed  Tiangong-2 space laboratory, and completed out a further refuelling operation of the orbital facility.

An artist’s impression of Tianzhou-1 (left) docked with the slightly larger Tiangong-2 orbital laboratory. Credit: CMSE

Launched in April 2017, Tianzhou-1 (“Heavenly Ship 1”) is the first of a series of resupply vehicles based on China’s first orbital module, Tiangong-1, designed to deliver up to 6.5 tonnes of equipment, supplies and fuel to orbital facilities – most notably China’s space station, construction of which is due to commence in 2018.

The 10.6m (34ft) long, 13 tonne Tianzhou-1 being prepared for installation into its launch shroud, April 2017. Image: CCTV

Tianzhou-1 is currently on an extended mission with the Tiangong-2 (“Heavenly Palace 2”) orbital facility, during which automated dockings at each of the laboratory’s two airlock systems are being practised, as is the transfer of fuel to the laboratory. The latter is a complicated, 29-step process, but one vital to the success of an orbital facility, where fuel is used in very small motor systems to help it maintain the correct orientation whilst in orbit and – potentially – help periodically boost the facility orbit to counter the microscopic (but cumulative) effect of atmospheric drag encountered whilst orbiting the Earth.

However, as such “boosts” to a space station’s orbit are more normally provided by an attached vehicle (the space shuttle used to do it for the International Space Station, for example, and the role has been taken over by the resupply craft which periodically visit the ISS). To this end, part of the Tianzhou-1 mission has also been to practice manoeuvring both the vehicle and  Tiangong-2 when the two have been docked. In addition, Tianzhou-1 has been carrying out its own free flight mission when not docked with the laboratory.

Like the European Automated Transfer Vehicle (ATV), Japanese H-II Transfer Vehicle (HTV) and American Cygnus resupply craft used in support of ISS operations, Tianzhou-1 is not designed to return to Earth. Instead, the vehicle will be allowed to burn-up as it re-enters the denser part of the Earth’s atmosphere at the end of its mission.

Following the Tianzhou-1 mission, a further crew of Chinese tiakonauts is expected to visit Tiangong-2 laboratory.

Kepler’s Latest Findings

NASA will announce the latest crop of planet discoveries from the Kepler Space Telescope on Monday, June 19th.

An artistic concept demonstrating gravitational microlensing. As an exoplanet passes in front of a more distant star, its gravity causes the trajectory of the starlight to bend, and in some cases results in a brief brightening of the background star as seen by a telescope, enabling scientists to search for exoplanets that are too distant and dark to be detected any other way (Credit: NASA / JPL / T. Pyle)

Kepler has been hunting for extrasolar planets since its launch in 2009, although the programme was almost cut short in 2013, following the failure of two of the reaction wheels (essentially gyroscope systems) used to stabilise the platform and allow it to gather data.

However, in November 2013, a new mission for the platform, dubbed “Second Light” and more generally referred to as the K2 mission,  was proposed and, after a successful period of test in early 2014, officially got under way on May 26th, 2014.

Most recently, Kepler has been using gravitational microlensing in an attempt to locate planets  orbiting stars so far away, the dimming of the star’s light by a transiting planet cannot easily be detected.

Kepler was the first mission capable of seeing planets the size of Earth around other stars in the “habitable zone” — the region at a distance from a star where liquid water could exist without freezing or boiling away immediately.

Thus far Kepler has found 4,496 exoplanet candidates. Some 2,335 have been confirmed and 21 are Earth-size planets in the habitable zone. Further, 520 of these exoplanet candidates have been found during the K2 mission, with 148 confirmed as having planets.

Continue reading “Space Sunday: Jupiter, exoplanets, Opportunity, and Wow! again”

Advertisements

SL14B: Celebrating Second Life

SL14B Community Celebration; Inara Pey, June 2017, on Flickr SL14B Community Celebration – click any image for full size

Second life celebrates its 14th year as an open virtual world on Friday, June 23rd, 2017. This means that once again, the Second Life Birthday Community Celebration is taking place in-world to mark the platform’s anniversary.

SL14B officially opened its gates at midday SLT on Sunday, June 18th, and events run through until Sunday, June 25th. The regions will then be open for viewing for a further week, although there will be no major entertainments or activities during that time. I’ve been fortunate enough to help out in the background for the event, and so have been watching the infrastructure and exhibitor builds take shape, and I have to say that people have really risen to this year’s theme of Carnivaleqsue.

The infrastructure builds at this years events comprise the expected roads and stages – the Cake Stage, Live Stage, DJ Stage and Stage Left – together with the Auditorium build, Welcome Area, Time Capsules display, and Max Mystery Land. With the exception of the Tim Capsules display, each covers between one and two regions (with the Cake Stage centred on its usual four regions), and offer some amazing interpretations of the celebration theme, and I have little doubt they’ll all be seeing a lot of use during the festivities.

SL14B Community Celebration; Inara Pey, June 2017, on Flickr SL14B Community Celebration

For the DJ Stage, Cynimon Catnap offers  a lush forest environment with tall trees and rich colours – and which hides what feels like an entire circus within it. Giraffes offer a welcome, giant carved lions give airborne acrobats the chance to test their skills, while paths wind among the trees, leading the way to carousels, Ferris wheels, bumper cars – and hidden glades where people can escape the inevitable rush. And, of course, topping  it all, literally as well as figuratively, is the DJ Stage, standing atop – what else? – the circus ringmaster’s beautifully adorned top hat!

Facing the DJ Stage across the width of the SL14B regions is the Welcome Area, by Darkstone Aeon. This is intended to be the starting point for visits to SL14B, containing information, Teleport boards, details of scheduled events and more. All this is set within a rocky environment, with an oriental lean to it. Great Chinese-style dragons (always at the centre of festivals) undulate over and through (literally!) the landscape, or stand on high peaks keeping an eye on everything. Follow the steps cut into the rock and the paths and ways carefully, for there is much to see here. Should you grow tired, or wish an alternate view of the region – be sure to take one of the dragon or balloon rides!

SL14B Welcome Area and Teleports; Inara Pey, June 2017, on Flickr SL14B Welcome Area and Teleports

To the south, and between both the DJ Stage and the Welcome Area, you’ll find the Auditorium, once again built by ADudeNamedAnthony. This year we have a design of clean, modern lines which carry within them a hint of Art Deco. Surrounded by broad avenues and bracketed by parkland, the Digital City venue would look at home in almost any city environment. Within it can be found the main auditorium, which will be home to talks and presentations throughout the week, supported by two smaller forum halls.

South of the Auditorium rises the Cake Stage. This is once again another of Mikati Slade’s gloriously colourful and distinctive designs, occupying the central corners of four adjoining regions. It will feature many activities and parties throughout the week including the Lab’s Masked Ball (Monday, June 19th 11:00 13:00 SLT) and Come As You Were party (Wednesday, June 21st 18:00 – 20:00 SLT) – find out more about these two events here.

SL14B Auditorium; Inara Pey, June 2017, on Flickr SL14B Auditorium

East of the Cake Stage, and occupying two regions, is the Live Music stage, designed by Chic Aeon. A curious design, the live stage sits within a mini urban setting which merges glowing building blocks with Monopoly like buildings. Caught in darkness (set your viewer to midnight if your environment doesn’t automatically change), it offers the neon feel of a city, beyond which, when facing the right direction, the glowing mass of the Cake Stage rises.

To the west and a little south of the Cake Stage is Stage Left, designed by Faust Steamer, and while I shouldn’t perhaps have favourites, I have to say it is one of the two infrastructure builds I particularly like at SL14B. Those who recall Faust’s Stage Left from SL13B are sure to be blown away by this year’s design, which again takes a fantastical twist on the carnivale theme for the celebrations, throwing in a Hindu incarnation of Cerberus, together with some Chinese influences.

SL14B Stage Left; Inara Pey, June 2017, on Flickr SL14B Stage Left

The scale of this build is just amazing; to really appreciate it, you have to cam out; to understand the sheer power evoked by it, simply stand next to the teleport dias / pool and look up as the great armoured beast lowers its middle head to look at you. This build also uses a local experience for teleporting – jump into the teleport pool and allow the experience too be lifted to the stage up on the beast’s broad back.

The other build we particularly enjoyed in our pre-opening ramblings and photo-gathering is the Max Mystery Land (aka Community Park), designed by Lim Pikajuna. Occupying a single region at the southern end of the Community Celebration estate, this offers all manner of entertainments above ground, in the air, underground and even under water. A theme park on (and in) a mountain, Max Mystery presents visitors with sky cars, go karts, pedaloes, boat rides, underwater bumpers cars, a disco, a mono-rail – there’s even a chapel!

SL14B Max Mystery Land; Inara Pey, June 2017, on Flickr SL14B Max Mystery Land

In addition to all this comes the exhibitor builds and displays. As usual, these are an eclectic, tumbling mix of designs and expressions, encompassing art in all its forms, promoting communities, commemorating individuals, showcasing skills, and of course offering fun and amusement or opportunities for quiet contemplation. Many have entered into the theme of the celebrations with gusto and imagination, making wandering the exhibitor regions a delight. Some have opted for displays pretty close to previous years’ offerings, and one or two still have yet to learn that slapping textures on prims that reach up into the sky might be eye-catching, but not necessarily in a positive way.

I’ll have more to say on exhibits and art at SL14B in the week. For now, I’ll leave you with the key SLurls – you can find a full list on the SL14B website, where you can also find the celebrations schedule (use the drop-down menu for individual stage, etc., schedules).

SL14B Core SLurls

All regions rated General.