. 24/7 Space News .
OUTER PLANETS
Mysteries of Uranus' oddities explained by Japanese astronomers
by Staff Writers
Tokyo, Japan (SPX) Apr 30, 2020

Uranian spin, orbit, and its satellite orbits Uranian spin axis is tilted from its 'orbit normal' by 98 degrees. Its satellite orbit normals coincide with the spin axis.

The ice giant Uranus' unusual attributes have long puzzled scientists. All of the planets in our Solar System revolve around the Sun in the same direction and in the same plane, which astronomers believe is a vestige of how our Solar System formed from a spinning disc of gas and dust. Most of the planets in our Solar System also rotate in the same direction, with their poles orientated perpendicular to the plane the planets revolve in. However, uniquely among all the planets, Uranus' is tilted over about 98 degrees.

Instead of thinking about the reality of stars spread in all directions and at various distances from the Earth, it is easier to understand by envisioning the celestial sphere. To picture what the celestial sphere is, look up at the night sky and imagine that all of the stars you see are painted on the inside of a sphere surrounding the Solar System. Stars then seem to rise and set as the Earth moves relative to this 'sphere'.

As Uranus rotates and orbits the Sun, it keeps its poles aimed at fixed points with relation to this sphere, so it appears to roll around and wobble from an Earth observer's perspective. Uranus also has a ring system, like Saturn's, and a slew of 27 moons which orbit the planet around its equator, so they too are tipped over.

How Uranus' unusual set of properties came to be has now been explained by a research team led by Professor Shigeru Ida from the Earth-Life Science Institute (ELSI) at Tokyo Institute of Technology. Their study suggests that early in the history of our Solar System, Uranus was struck by a small icy planet - roughly 1-3 times the mass of the Earth - which tipped the young planet over, and left behind its idiosyncratic moon and ring system as a 'smoking gun'.

The team came to this conclusion while they were constructing a novel computer simulation of moon formation around icy planets. Most of the planets in the Solar System have moons, and these display a menagerie of different sizes, orbits, compositions and other properties, which scientists believe can help explain how they formed. There is strong evidence Earth's own single moon formed when a rocky Mars-sized body hit the early Earth almost 4.5 billion years ago. This idea explains a great deal about the Earth and its Moon's composition, and the way the Moon orbits Earth.

Scientists expect such massive collisions were more common in the early Solar System, indeed they are part of the story of how all planets are thought to form. But Uranus must have experienced impacts that were very different from Earth simply because Uranus formed so much farther from the Sun. Since the Earth formed closer to the Sun where the environment was hotter, it is mostly made of what scientists call 'non-volatile' elements, meaning they don't form gases at normal Earth-surface pressures and temperatures; they are made of rock.

In contrast, the outermost planets are largely composed of 'volatile' elements, for example things like water and ammonia. Even though these would be gases or liquids under Earth-surface like temperatures and pressures, at the huge distances from the Sun the outer planets orbit, they are frozen into solid ice.

According to professor Ida and his colleagues' study, giant impacts on distant icy planets would be completely different from those involving rocky planets, such as the impact scientists believe formed Earth's Moon. Because the temperature at which water ice forms is low, the impact debris from Uranus and its icy impactor would have mostly vapourised during the collision.

This may have also been true for the rocky material involved in Earth's Moon-forming impact, but in contrast this rocky material had a very high condensation temperature, meaning it solidified quickly, and thus Earth's Moon was able to collect a significant amount of the debris created by the collision due to its own gravity. In the case of Uranus, a large icy impactor was able to tilt the planet, give it a rapid rotation period (Uranus' 'day' is presently ~ 17 hours, even faster than Earth's), and the leftover material from the collision remained gaseous longer.

The largest mass body, what would become Uranus, then collected most of the leftovers, and thus Uranus' present moons are small. To be precise, the ratio of Uranus' mass to Uranus' moons' masses is greater than the ratio of Earth's mass to its moon by a factor of more than a hundred. Ida and colleagues' model beautifully reproduces the current configuration of Uranus' satellites.

As Professor Ida explains, 'This model is the first to explain the configuration of Uranus' moon system, and it may help explain the configurations of other icy planets in our Solar System such as Neptune. Beyond this, astronomers have now discovered thousands of planets around other stars, so-called exoplanets, and observations suggest that many of the newly discovered planets known as super-Earths in exoplanetary systems may consist largely of water ice and this model can also be applied to these planets.'

Research Report: "Uranian satellite formation by evolution of a water vapour disk generated by a giant impact"


Related Links
Tokyo Institute of Technology
The million outer planets of a star called Sol


Thanks for being there;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Monthly Supporter
$5+ Billed Monthly


paypal only
SpaceDaily Contributor
$5 Billed Once


credit card or paypal


OUTER PLANETS
The birth of a "Snowman" at the edge of the Solar System
New York NY (SPX) Apr 23, 2020
A model developed at the Faculty of Physics at the Technion, in collaboration with German scientists at Tubingen, explains the unique properties of Arrokoth - the most distant object ever imaged in the solar system. The research team's results shed new light on the formation of Kuiper Belt objects, asteroid-like objects at the edge of the Solar system, and for understanding the early stages of the solar system's formation. The researchers' findings, published in the Nature, explain the unique char ... read more

Comment using your Disqus, Facebook, Google or Twitter login.



Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

OUTER PLANETS
180 day commercial Soyuz mission to ISS possible in 2022

Russian cargo capsule docks with ISS

CASIS welcomes new NASA ISS National Lab program executive

Russian 'Victory Rocket' cargo flight docks at ISS

OUTER PLANETS
US Military not sure if Iran's launch of 'military' satellite was successful

Solar One: A proposal for the first manned interstellar spaceship

Permanently open call for commercial space transportation services

NASA Test Directors eagerly await Artemis launch

OUTER PLANETS
Promising signs for Perseverance rover in its quest for past Martian life

Nanocardboard flyers could serve as martian atmospheric probes

Surface Hot Springs May Have Existed on Ancient Mars

Mars 2020 Perseverance rover gets balanced

OUTER PLANETS
China builds Asia's largest steerable radio telescope for Mars mission

China recollects first satellite stories after entering space for 50 years

China's first Mars exploration mission named Tianwen-1

Parachutes guide China's rocket debris safely to earth

OUTER PLANETS
Momentus selected as launch provider for Swarm

Elon Musk's SpaceX launches 60 Starlink satellites from Florida

SpaceX plans Wednesday Starlink satellite launch from Florida

US wants to mine resources in space, but is it legal?

OUTER PLANETS
Sensors woven into a shirt can monitor vital signs

Coding contest from NASA and Texas Instruments allows students to compete virtually to win out-of-this-world prizes

New Army tech may turn low-cost printers into high-tech producers

UAV Navigation integrates Sagetech Avionics' transponders for sense and avoidance

OUTER PLANETS
Yale's EXPRES looks to the skies of a scorching, distant planet

Researchers use 'hot Jupiter' data to mine exoplanet chemistry

Scientists find microbes eating ethane spewing from deep-sea vents

Hubble observes aftermath of massive collision

OUTER PLANETS
Jupiter probe JUICE: Final integration in full swing

The birth of a "Snowman" at the edge of the Solar System

New Horizons pushing the frontier ever deeper into the Kuiper Belt

Mysteries of Uranus' oddities explained by Japanese astronomers









The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.