Around 800 scientists from around the world met at the European Planetary Science Congress in Riga this week to present the latest findings on our home planet and Solar System.
Here, we present some of our favourite stories from this year’s conference.
European lunar lander location revealed
Images of the Moon taken by NASA’s Lunar Reconnaissance Orbiter have enabled the pinpointing of the impact location of ESA’s SMART-1 lunar spacecraft
(P Stooke/B Foing et al 2017/ NASA/GSFC/Arizona State University)
A lunar scientist has been able to pinpoint the final resting place of SMART-1, the first lunar mission by the European Space Agency which purposely impacted on the surface of the Moon 11 years ago.
At the time of the impact, the Canada-France-Hawaii Telescope was able to locate a flash caused by the impact of the spacecraft, but its exact location was not known.
The location is now confirmed as 34.262° south and 46.193° west.
It was discovered by Dr Phil Stooke of Western University, Ontario, Canada using images captured by NASA’s Lunar Reconnaissance Orbiter.
They show a gouge in the surface about 4m by 20m.
“SMART-1 had a hard, grazing and bouncing landing at two kilometres per second on the surface of the Moon,” says ESA SMART-1 Project Scientist, Bernard Foing.
“There were no other spacecraft in orbit at the time to give a close-up view of the impact, and finding the precise location became a ‘cold case’ for more than 10 years.
The next steps will be to send a robotic investigator to examine the remains of the SMART-1 spacecraft body and ‘wings’ of the solar arrays.”
Martian comet encounter complicated by solar winds
An image by the Hubble Space Telescope of Comet C/2013 A1 (Siding Spring), which made a close pass by Mars on 19 october 2015.
Credit: NASA, ESA, and J.-Y. Li (Planetary Science Institute)
Studies of the effects of a comet that made a close encounter with Mars have been complicated because of a wave of electrically charged particles that blasted out from the Sun at about the same time.
Comet C/2013 A1 (Siding Spring) passed 140,000 km from Mars on 19 October 2014, depositing debris in the Martian atmosphere.
Space agencies around the world coordinated spacecraft to observe what became the largest meteor shower in recorded history.
But analysis of the event has been complicated because of a powerful coronal mass ejection (CME) from the Sun that occurred 44 hours before the comet arrived.
Data from ESA’s Mars Express mission, NASA’s MAVEN and Mars Odyssey orbiters indicates showers of energetic oxygen ions and dust rained on Mars during the time the planet was engulfed by the comet’s outer atmosphere (its coma).
These ions were accelerated by a powerful ‘solar wind’ of charged particles and delivered into the Red Planet’s atmosphere.
But the amount of ionised water interacting with the Martian atmosphere was smaller than expected.
Analysis suggests that most of the ionised water from the comet was actually carried away by the solar wind, rather than dropping into Mars’s atmosphere.
Diamonds are a geologist’s best friend
A cathode luminiscence image of a polished diamond plate, revealing the diamond’s growth history. Analysis of diamonds has suggested they may have been created relatively recently, in geological terms.
Credit: Michael Gress
Earth may have produced diamonds more recently than thought, according to a study of the Venetia mine in South Africa.
The study suggests that some volcanic events on Earth may still be able to create the kind of hot conditions that were thought to only have existed early in the history of our planet, before it cooled.
Researchers from the Vrije Universiteit Amsterdam studied 26 diamonds that were formed under extreme conditions in Earth’s mantle.
They found two groups, one of which displayed geologically ‘young’ diamonds.
Nine have an age of about 3 billion years and are linked to volcanism caused by the breakup of an old continent.
But ten are dated at just over a billion years old, correlating with a volcanic event in Zimbabwe that occurred 1.1 billion years ago.
Craters proven to be of extra-terrestrial origin
The seabed relief of the Neugrund crater area. Is this the best preserved submarine crater we know of?
Credit: Sten Suuroja
Analysis of craters in the Baltic region has given scientists insights into the impacts that created them.
In Põlva County, Estonia, studies of Illumetsa, a pair of small craters, revealed small pieces of charcoaled tree fragments buried about 60 cm around the rim.
Carbon dating puts the formation of the craters at about 7,170 and 7,000 years ago, suggesting they both formed from a meteorite impact.
“Until now, the two craters had not been firmly proven to be of extraterrestrial origin: neither remnants of the projectile nor other identification criteria had been found up to this point,” says Dr Anna Losiak of the Polish Academy of Sciences in Warsaw.
Another study, this time of the Neugrund crater at the bottom of the sea in the Gulf of Finland, revealed it to have been formed 535 million years ago.
The projectile was about a kilometer in diameter and hit the sea where the depth was about 100 metres.
It was then buried under sediment and remained concealed until the Ice Age.
It could be the best preserved example of an undersea crater in the world.
Attack of the nano-spaceprobes
An artist’s concept of one of 50 nano-spacecraft that could visit over 300 asteroids in just over three years.
A fleet of spaceships could soon be leaving Earth to explore the asteroid belt.
A new project suggests sending 50 nano-spacecraft, powered by electric solar wind sails, to fly as close as 1,000 km from an asteroid to capture images and spectroscopic data.
Once the spacecraft have visited up to seven different asteroids, they would then return with their data to Earth.
“Asteroids are very diverse and, to date, we’ve only seen a small number at close range.
To understand them better, we need to study a large number in situ.
The only way to do this affordably is by using small spacecraft,” says Pekka Janhunen from the Finnish Meteorological Institute.
Bigger is better for planetary atmospheres
An artist’s impression of an exoplanetary system. Size, not mass, could be a key factor in whether a planet’s atmosphere can be detected.
It is size, rather than mass, that counts when it comes to exoplanet atmospheres.
This is the conclusion of a survey of 30 hot Jupiters that looked for gasses around the planets.
It found strong signs of an atmosphere around 16, all of which had water vapour in their atmosphere.
The survey found that the larger the planet was, the more likely it was to have an atmosphere, regardless of its mass, implying that gravitational pull has only a minor effect on the evolution of a planet’s atmosphere.
“30 exoplanet atmospheres is a great step forward compared to the handful of planets observed years ago, but not yet big-data.
We are working at launching dedicated space missions in the next decade to bring this number up to hundreds or even thousands,” says Giovanna Tinetti from University College London.
The devil’s in the dust
Samples of a dust devil are captured during field campaign ‘Morocco 2016’. The samples are still under analysis.
Credit: Jan Raack/Dennis Reiss.
Dust devils – swirling columns of dust and sand – could transport fine particles for thousands of kilometres on both Mars and Earth, according to a study by Dr Jan Raack of the Open University and an international team of scientists.
The vortices are often seen in the deserts of both planets, lifting particles of dust high into the atmosphere.
A study of dust devils on Earth found that around two thirds of the particles kicked up by a dust devil remain in the atmosphere after the phenomenon has stopped.
This amount of dust is large enough that it could impact the planet’s climate and weather.
However, dust devils on Earth are affected by the water in the atmosphere.
On a planet as arid as Mars, it’s thought that even more dust could remain suspended and have a much larger impact on the planet’s weather.