Starstuff – Dark Matter Maps, Exomoon Excitement and Cassini’s Close Shaves

Proudly supported by

  Last updated August 21, 2017 at 10:46 am

Topics:  

Find out what the universe delivered in the latest astronomy and astrophysics news with Starstuff every fortnight.

Dark Matter mapped

Dark matter is notoriously difficult to study. We’ve never observed it, but have observed its effects. We know it makes up around a quarter of the mass of the universe, but have never sampled it. And we know it’s everywhere, but have never located it.

Now Australian scientists have been part of a 400 strong team from around the world to create the most accurate measurement and map of dark matter in the universe. “The survey supports the view that dark matter and dark energy make up most of the cosmos,” said University of Queensland cosmologist Dr Tamara Davis of the 5 year project.

The Dark Energy Survey created a distribution map of dark matter in the cosmos by accurately measuring the position of galaxies. They then accurately measured the shape of 26 million galaxies using new techniques to detect and measure gravitational lensing – an effect when the gravity caused by mass bends light. This allowed them to detect the amount and “clumpiness” of dark matter based on how much gravitational lensing was occurring between the galaxy being observed and Earth – the more distortion of the shape of the galaxy, the more dark matter that was bending the light.

Not only is it the most accurate and largest measurement of dark matter, but it is also the first to measure dark matter in the universe as it is today. Previous measurements have been inferred from observations of the cosmic background radiation left over from the universe during its infancy. However combining the different data sources allows researchers to see the evolution of dark matter in the universe, and they found that it confirmed many predictions that had been previously made.

The results released are based only on the first year of data collected, representing around one thirtieth of the sky. After analysing all 5 years of data, the group will have mapped around one eighth of the sky up to eight billion light years away from Earth.

Dark matter map courtesy of Chihway Chang, University of Chicago and the DES collaboration

Cassini’s final orbits

The Saturn-investigating probe Cassini is preparing for its final orbits this week. Launched nearly 20 years ago and orbiting Saturn for 13 of those, Cassini is reaching the final weeks of its life but is saving the most ambitious plans for last.

Beginning on 14 August Cassini will plunge closer to Saturn than ever before, passing within 1700 kilometres of the cloud tops. This puts it far enough inside Saturn’s atmosphere that it will need to actively use its thrusters to maintain stability.

During these close passes Cassini will be sampling Saturn’s atmosphere and using an on board radar to map the lower reaches of the atmosphere in fine detail (or at least features down to 25km in size). Given how little we know about Saturn’s lower atmosphere, this information will be vital to understand the make up of the planet and will help design future missions to the planet.

Following the close passes Cassini will make a final lap of the moon Titan to place it on a terminal trajectory back towards Saturn. On September 15 Cassini will plunge down through the Saturnian atmosphere for the last time, transmitting as much information about the planet as it can before it eventually burns up in the ever increasingly dense atmosphere.

This final plunge and fiery death in Saturn’s atmosphere is not only Cassini’s final scientific gesture, but also an important step in the conclusion of its mission. By burning up the satellite in the atmosphere of Saturn, the scientists not only dispose of the satellite but also destroy any hitchhiking bacteria from Earth. Had Cassini been allowed to crash into one of Saturn’s moons instead, the lack of atmosphere could have resulted in bacteria surviving the crash and contaminating the surface. And as the moons of Saturn are candidates for harbouring life, contamination by Earth-bound bacteria would be an unmitigated disaster for understanding the development of life elsewhere in the universe. In this case, Cassini’s death is far preferred to life.

Cassini image courtesy of NASA

Einstein proven correct, again

Einstein’s theories of relativity are now over 100 years old, and over the intervening century have had numerous challenges. However time and time again the theories hold true. Recently German and Czech astronomers have again confirmed the theories hold true even under extreme conditions.

The group studied the behaviour of a cluster of three stars closely orbiting the supermassive black hole in the centre of the Milky Way. Orbiting the black hole extremely closely by galactic standards – the equivalent of 100 times the distance between the Earth and the Sun, the stars are subjected to an incredibly strong gravitational field. Their proximity also means they travel at around 1 or 2 percent of the speed of light, and even in these extreme conditions one of the stars exhibited changes in the shape of its orbit caused by gravity which fits with Einstein’s predictions.

The behaviour of objects in gravitational fields has been used to prove Einstein’s laws of relativity previously, however usually by examining the movement of planets around stars such as our Sun. This is the first time scientists have been able to make precise measurements of objects orbiting a black hole with a mass equivalent to 4 million Suns, where the conditions are wildly different.

Considering the age of Einstein’s theories and the information available to him when they were conceived, for the theories to be accurate even in conditions that Einstein could never have considered shows just how incredible and robust they are. One day physicists might be able to find a condition that doesn’t fit the rules, but it seems today is not that day.

Orbits of stars image courtesy of ESO,M. Parsa and L. Calçada

Move over exoplanets, have we just found an exomoon?

Astronomers around the world have had quite a lot of recent success discovering and identifying exoplanets – planets which orbit stars which aren’t our sun. However the search for exomoons – satellite planets which orbit those exoplanets, has been far less successful. Promising discoveries have evaporated literally before the astronomy community’s eyes as they study results further and revisit potential candidates with more advanced equipment, meaning we’re still yet to find an exomoon.

This history of disappointment was the reason astronomer David Kipping from Columbia University wanted to keep his preliminary findings close to his chest until he had more definitive results. However his quest for secrecy was foiled when another astronomer noticed, and tweeted about, Kipping’s request for the Hubble Space Telescope to collect images of an exoplanet for his research. Kipping is a prominent astronomer in the search for exomoons so a request for time to use Hubble could only mean one thing – he was hunting a candidate exomoon.

With the astronomer’s tweet about Kipping’s request creating a buzz on the internet, Kipping’s team decided to come clean and announce their potential discovery, publishing the early results on the pre-print website arXiv. “It wasn’t something we were planning on announcing, because at this point it’s only a candidate,” says Kipping, who wanted to be more cautious with the news.

The candidate exomoon, Kepler-1625b I, had been observed orbiting a planet 4,000 light years from Earth. The exoplanet Kepler-1625b had been observed transiting across the face of its star by measuring dips in light as it blocked part of the star’s face. However those dips were found to be lopsided, suggesting not one object but two. After analysing this lopsidedness it was thought the Jupiter-sized planet Kepler-1625b had an unexpectedly huge Neptune-sized moon, named Kepler-1625b I.

The reason for the secrecy was not to prevent other scientists from studying the candidate exomoon before Kipping could confirm his results, but instead to prevent the media storm that has surrounded other candidate exomoon announcements. “Let’s be clear: we’re not just trying to save ourselves from embarrassment,” team member Alex Teachey wrote in Scientific American. “The announcement and subsequent retraction of potentially ground-breaking results has the effect of eroding public trust in science over time, and we are chiefly concerned with not contributing to that problem.”

Hubble will examine the candidate exomoon in October, and the team hope to make a definitive statement about what they have found around six months after.

Hubble image courtesy of NASA and STScI

Follow us on Facebook, Twitter and Instagram to get all the latest science.




About the Author

Ben Lewis
Ben Lewis is the Editor of Australia’s Science Channel, and a contributor to Cosmos Magazine. He has worked with scientists and science storytellers including Brian Cox, Chris Hadfield, Robert Llewellyn, astronauts, elite athletes, Antarctic explorers, chefs and comedians. Ben has also been involved in public events around Australia and was co-writer, producer and director of The Science of Doctor Who, which toured nationally in 2014 in association with BBC Worldwide Australia & New Zealand. Want more Ben? You can hear him on ABC and commercial radio in Adelaide, regional SA, across NSW, and the ACT. He also speaks at universities around Australia on communicating science to the public. Around the office he makes the worst jokes known to mankind.

Published By

Science and technology is as much a part of our cultural fabric as art, music, theatre and literature. They play a significant role in our daily lives, yet, in a world dependent on science, we often take them for granted. Australia’s Science Channel believes every citizen has a right, and a responsibility, to be informed, and our mission is to create programs to bring that about.


Featured Videos

Placeholder
Columbia: NASA blew it
Placeholder
The Face of a Stranger
Placeholder
Where Does Space Begin?
Placeholder
The Rarest Drug on Earth
Placeholder
Why is blue so rare in nature
Placeholder
Ant Sisters
Placeholder
Jeremy the Lefty Snail and Other Asymmetrical Animals
Placeholder
Tracking Snow
Placeholder
Smart Slime?
Placeholder
Good in the machine
Placeholder
Kessler Syndrome: What happens when satellites collide?
Placeholder
Why This Skateboarding Trick Should Be Impossible
Placeholder
Charles Camarda on becoming an astronaut
Placeholder
Alan Duffy on what it took to get humans to the Moon
Placeholder
Do aliens exist? Brian Cox explains
Placeholder
From Apollo to Pulsars: Parkes still dishing out the discoveries
Placeholder
Brian Cox on black holes
Placeholder
Australia's 60,000 years of space history
Placeholder
In Class With… Jane Goodall
Placeholder
Etienne Rastoin-Laplane - What's fishy about the Galapagos?
Placeholder
Kit Prendergast - Flowers to keep native bees buzzing
Placeholder
Rebecca Wellard - Eavesdropping on killer whales
Placeholder
Hossein Tavassoli - Mending broken hearts
Placeholder
Dilan Seckiner - Forensic gait analysis
Placeholder
Samuel Bladwell - A new spin on electronics
Placeholder
Sathana Dushyanthen - The double-edged cancer sword
Placeholder
Dwan Price - Nuts and Guts
Placeholder
Catriona Nguyen-Robertson - Exercise takes your immune system for a ride
Placeholder
Thimo Ruethers - The deadly danger of crocs on a plate
Placeholder
Amanda Tauber - Slamming the brakes on metastatic cancer
Placeholder
Hayley Teasdale – The ball that prevents falls (FameLab Australia 2019 Runner-up)
Placeholder
In the Shadow of a Black Hole
Placeholder
In Class With... Monica Gagliano
Placeholder
In Class With... Brian Cox
Placeholder
Start your FameLab 2019 journey now
Placeholder
Nural Cokcetin - It all starts with FameLab
Placeholder
Erinn Fagan-Jeffries - It all starts with FameLab
Placeholder
Ronald Yu - It all starts with FameLab
Placeholder
Noushin Nasiri - It all starts with FameLab
Placeholder
Grassroots
Placeholder
What is machine learning?
Placeholder
Mythbusting artificial intelligence with expert Anton van den Hengel
Placeholder
Using machine learning to predict medical outcomes
Placeholder
KCLOC
Placeholder
Nature Calls
Placeholder
Mexican Fishing Bats
Placeholder
Bittersweet
Placeholder
Timelapse
Placeholder
Invisible Blanket
Placeholder
Look
Placeholder
The Anomalies: Venom Race
Placeholder
Science Meets Making
Placeholder
Spiral
Placeholder
Looking Out There
Placeholder
Protectors of the Penguins
Placeholder
Astroturf
Placeholder
Virtual Humans
Placeholder
Rancheros del Jaguar
Placeholder
Searching For Dark Matter
Placeholder
Finding prehistoric mega-shark fossils on Victoria's coast
Placeholder
The Grandfather of computers
Placeholder
James Cameron talks science
Placeholder
In Class With.....David Suzuki - The Environment
Placeholder
In Class With.....David Suzuki - Career
Placeholder
Sustainable water use with Doug Green
Placeholder
Why is Indigenous science important?
Placeholder
Vanessa Pirotta - Using drones to collect whale snot (FameLab Australia 2018 Winner)
Placeholder
Toby Hendy - Poking Plants (FameLab Australia 2018 Runner-Up)
Placeholder
Muthu Vignesh Vellayappan - Groovy Patches (FameLab Australia 2018 Audience Choice)
Placeholder
Taryn Laubenstein - The Tail of Two Fishes
Placeholder
Richard Charlesworth - Coeliac disease diagnosis can be a pain in the posterior
Placeholder
Pegah Maasoumi - Solar Windows
Placeholder
James Wong - Breathing while you hop: How do kangaroos do it?
Placeholder
Ben McAllister - The ORGAN Experiment: Shining a light on dark matter
Placeholder
Mortaza Rezae - Empowering beautiful minds
Placeholder
Zane Stromberga - Can allergy drugs beat bladder disease?
Placeholder
Working In.....Art - Astrophotography
Placeholder
What's the best way to move - springs or muscles?
Placeholder
FameLab Australia Semi-Final Highlights
Placeholder
Saving lives with platypus milk
Placeholder
Australian astronomers witness death throes of a cocooned star
Placeholder
How Australia's politicians see our future in space
Placeholder
Keeping satellites in the loop
Placeholder
Tim Flannery talks about COP
Placeholder
Tim Jarvis & Tim Flannery talk Climate Change
Placeholder
Andy's Week in Science - robo baby, university rankings, and cancer on circadian rhythms
Placeholder
From chocolate factory to surgery - the milliDelta robot
Placeholder
Andy's Week in Science: video games, low tech transition windows and a new CRISPR technique
Placeholder
Science lessons useful in Art Restoration career
Placeholder
Are drones the future of racing?
Placeholder
The future of esports according to the experts
Placeholder
Seeing is believing with artist Eugenie Lee
Placeholder
The human impact of Art Science collaboration
Placeholder
Follow your Interests in Robotics
Placeholder
Zoz on 3D Printing
Placeholder
Flavia Tata Nardini on women in engineering
Placeholder
Flavia Tata Nardini on the future of the internet
Placeholder
Explore the ocean floor and Antarctic biodiversity
Placeholder
Follow your interests in Medical Research
Placeholder
Artists on Science
Placeholder
What is Space Archaeology?
Placeholder
Follow your Interests
Placeholder
Scientists on Art
Placeholder
3D Printing in Medical Research
Placeholder
Ethical Issues
Placeholder
Problem Solving - Robotics at Dermatec
Placeholder
Problem Solving with CSI
Placeholder
Tamarah King - Earthquake Geologist
Placeholder
True or False with Bajo and Rad BONUS ROUND
Placeholder
True or False with Bajo & Rad
Placeholder
Andy's Week in Science - Cats vs Dogs
Placeholder
FameLab 2018 - Get Involved!
Placeholder
Nural Cokcetin - How FameLab changed my life
Placeholder
Erinn Fagan-Jeffries - How FameLab changed my life
Placeholder
Noushin Nasiri - How FameLab changed my life
Placeholder
Ronald Yu - How FameLab changed my life
Placeholder
Alan Duffy's Top 5 Science Communication Tips
Placeholder
A Judge's Top Tips for FameLab Australia
Placeholder
Brain Candy - Why, Why, Why Michael Stevens?
Placeholder
The Past, Present, and Future of Malaria
Placeholder
This is a video of poo pills being made!
Placeholder
Mind Games - Sports Psychology
Placeholder
Fuel to Win - Sports Nutrition
Placeholder
Fifty years since Australia beat the world to space
Placeholder
ECR Network: Talk Your Science with Alan Duffy
Placeholder
Andy's Week in Science - chimps, klompen, and clouds
Placeholder
Our robot medicine future - heart huggers and micro biohybrids
Placeholder
Six Awkward Cancer Questions
Placeholder
How do you tell if a whale is left-handed?
Placeholder
She Flies - Turning Girls into Drone Pilots
Placeholder
Andy's Week in Science - Magnetic Fabric, Cancer Treatments, and Echolocation
Placeholder
The Science of Sexuality
Placeholder
Sailing Through Space with Bill Nye
Placeholder
Using Sports Science to Help Olympic Athletes
Placeholder
Three and a Half Minutes of Top Shelf Career Advice
Placeholder
New Space Tech with Andrea Boyd
Placeholder
Kelly Meets the Mars Curiosity Rover
Placeholder
Hearts, Opera, and Tough Conversations - Andy's Week in Science
Placeholder
Bill Nye on Science, Girls, and Saving the World!
Placeholder
2017 Prime Minister's Prizes for Science Part 2
Placeholder
2017 Prime Minister's Prizes for Science Part 1
Placeholder
Who Decides the Law in Space?
Placeholder
Scientists Watch Collision That Created Gravitational Waves
Placeholder
Getting Cold Feet Leads to a Whole New Career
Placeholder
ECR Network - Why Every Scientist Should Be on Twitter - The Benefits
Placeholder
ECR Network - Why Every Scientist Should Be On Twitter - The Fears
Placeholder
Live Podcast - Life Vs Science
Placeholder
Origami Robots, Babies, and Kidneys - Andy's Week in Science
Placeholder
Namira Salim and the Zero-G Peace Summit
Placeholder
Elon Musk's Mars Plan: Expert Analysis
Placeholder
SPACE AF - Thursday
Placeholder
My Time in Space
Placeholder
IAC TV Daily Broadcast - Wednesday
Placeholder
SPACE AF - Wednesday
Placeholder
IAC TV Daily broadcast - Tuesday
Placeholder
SPACE AF - Tuesday
Placeholder
IAC TV daily broadcast - Monday
01:00:41
Placeholder
SPACE AF - Monday
Placeholder
Live from IAC 2017
Placeholder
Brew Ha Ha - Technology Rewrites History
Placeholder
Methamphetamine - Gateway Drug to Parkinson's Disease
Placeholder
Concussion, 3D BioPrinting, and The Universe - Andy's Week in Science
Placeholder
Pulsars, Clearwigs, and Pacemakers - Andy's Week in Science
Placeholder
Revolutions - The Quest to Transform HPV Racing
Placeholder
Brew Ha Ha - Hurricane Irma Blows Away Tesla's Rip Off
Placeholder
Brew Ha Ha - The Limit of Your Lifespan
Placeholder
The Recipient
Placeholder
Think Like a Scientist: Natural Selection in an Outbreak
Placeholder
The End of Snow
Placeholder
The Next Rembrandt
Placeholder
The Discarded
Placeholder
The Spectators
Placeholder
Test Tube Babes
Placeholder
Pangolins in Peril- A Story of Rare Scales
Placeholder
Rock Art Project
Placeholder
Pork.0
Placeholder
OWSIA (Darkened Water)
Placeholder
Nex
Placeholder
Northern Quolls
Placeholder
Dish Life
Placeholder
At Street Level
Placeholder
Custom Love
Placeholder
Adrift
Placeholder
A Story from Space
Placeholder
Brew Ha Ha - The Most Dangerous Thing in Boxing May Be the Gloves
Placeholder
ECR Network 2017 – Get Interdisciplinary!
01:27:00
Placeholder
Chris Hadfield: The Future of Space Exploration
Placeholder
Chris Hadfield: Life After Space
Placeholder
Chris Hadfield: Life in Space
Placeholder
Brew Ha Ha - Let's Make Algae Australian of the Year
Placeholder
Brew Ha Ha - Australia's Energy Showdown
Placeholder
Nine Awkward Astrophysicist Questions
Placeholder
Brew Ha Ha - There's No Such Thing as an Exercise Pill
Placeholder
National Science Week Awards Show
Placeholder
Brew Ha Ha - Your 5 Step Asteroid Success Plan
Placeholder
National Science Week Forecast
Placeholder
Open Doors. Open Future. Open Day.
Placeholder
Brew Ha Ha - Lose a Little to Gain Millions
Placeholder
Brew Ha Ha - Crowd Sourcing Origami Astronaut Protection
Placeholder
Brew Ha Ha - T-Rex's Prehistoric Power Walk
Placeholder
True or False with Kale Brock
Placeholder
The Grandfather Paradox
Placeholder
Brew Ha Ha - The Hidden Heroes Tackling Mozzies
Placeholder
Brew Ha Ha - Emergency AI Assistance
Placeholder
Brew Ha Ha - Frogs Forever, Dinosaurs Never!
Placeholder
Brew Ha Ha - Australia, Let's Go To Space
Placeholder
Brew Ha Ha - Welcome to the Microbiome, Archaea!
Placeholder
Brew Ha Ha - Roos Blindside Driverless Cars
Placeholder
Biodiversity of Antarctica Under Threat From Increase In Ice-Free Areas
Placeholder
Brew Ha Ha - The Future of the Census
Placeholder
Tell Me! Brian Cox
Placeholder
Crash, Burn, Tweak, Repeat
Placeholder
Brew Ha Ha - Humans Just Got Older and Wiser
Placeholder
Brew Ha Ha - Cheers to Brain Health?
Placeholder
Gene Therapy Could Cure Allergies
Placeholder
Brew Ha Ha - iHeart Hacking
Placeholder
Ridiculology - New Hubble
Placeholder
Brew Ha Ha - Trees Alone Can't Save Us
Placeholder
Brew Ha Ha - Earth's Accidental Force Field
Placeholder
Dinosaurs on the Big Screen
Placeholder
Brew Ha Ha - Farewell MP3
Placeholder
Kids Beat Grown-ups on Pneumonia Vaccines
Placeholder
Brew Ha Ha - The Booger Conspiracy
Placeholder
FameLab 2017 National Final - Part 2
Placeholder
FameLab 2017 National Final - Part 1
Placeholder
2017 Budget Response
Placeholder
What Are Animal Weapons?
Placeholder
If You Love Both Art and Science, Be a Scientific Illustrator
Placeholder
Getting Personal With Skinks
Placeholder
Brew Ha Ha - CSIRO Email Leaks
Placeholder
FameLab 2017 Western Australia Semi-Final Highlights
Placeholder
Brew Ha Ha - New Hope for Premmies
Placeholder
Brew Ha Ha - Britain Goes Coal-Free
Placeholder
Brew Ha Ha - Naked Mole-Rats (SFW)
Placeholder
Brew Ha Ha - Easter Reminders
Placeholder
Meet Andrea Boyd - Space Flight Controller
Placeholder
Brew Ha Ha - Sperm Drug Smugglers
Placeholder
FameLab 2017 New South Wales Semi-Final Highlights
Placeholder
The Science of Fiction
Placeholder
Brew Ha Ha - Liquorice Poisoning
Placeholder
Brew Ha Ha - Crowdsourcing Science
Placeholder
FameLab 2017 Queensland Semi-Final Highlights
Placeholder
Brew Ha Ha - SpaceX Preps for Relaunch
Placeholder
Poly Cystic Ovary Syndrome Breakthrough
Placeholder
Brew Ha Ha - Surviving a Media Storm
Placeholder
Will This Aussie Team Win the Race to Create the Ultimate Malaria Vaccine?
Placeholder
Brew Ha Ha - New Dino Family Tree
Placeholder
How to fix things with Kyle Wiens
Placeholder
Repair or replace? iFixit co-founder Kyle Wiens