Meteorite impact caused long-lived volcanic eruptions on Earth

meteorite impact volcanic eruptions sudbury

A photomicrograph of a vesicular green shard from the Onaping Formation of the Sudbury impact basin. Credit: Paul Guyett, Trinity College Dublin.

Meteorite impacts can produce more than craters on the Earth – they can also spark volcanic activity that shapes its surface and climate by bringing up material from depth. That is the headline finding of an international team, led by geochemists from Trinity College Dublin, who discovered that large impacts can be followed by intense, long-lived, and explosive volcanic eruptions.

The team studied rocks filling one of the largest preserved impact structures on the planet, located in Sudbury (Ontario, Canada). The ‘bolide’ hit the Earth here 1.85 billion years ago and excavated a deep basin, which was filled with melted target rocks and, later, with jumbled mixed rocks full of tiny volcanic fragments.

Not only are there volcanic fragments throughout the sequence of the 1.5 km-thick basin but they have a very distinctive angular shape, which the scientists explain resembles a ‘crab claw’. Such shapes form when gas bubbles expand in molten rock that then catastrophically explodes—a feature of violent eruptions involving water, and which can be seen under glaciers in Iceland, for example. In the crater, these took place for a long period of time after the impact, when the basin was flooded with sea water.

The key finding of the research, just published in the Journal of Geophysical Research: Planets, is that the composition of the volcanic fragments changed with time. Right after the impact, volcanism is directly related to melting of the Earth’s crust. However, with time, volcanism seems to have been fed by magma coming from deeper levels within the Earth.

Professor of Geology and Mineralogy at Trinity, Balz Kamber, said: “This is an important finding, because it means that the magma sourcing the volcanoes was changing with time. The reason for the excitement is that the effect of large impacts on the early Earth could be more serious than previously considered.”

On the early Earth there was a relatively brief period during which ca. 150 very large impacts occurred, whereas since then, only a handful have hit the Earth.

Professor Kamber added: “The intense bombardment of the early Earth had destructive effects on the planet’s surface but it may also have brought up material from the planet’s interior, which shaped the overall structure of the planet.”

The findings raise interest in topical research on similar volcanism on other planetary bodies like Mercury, Venus, Mars and the Moon. There, unlike on the Earth, the lack of plate tectonics and erosion help preserve surface features, which are probed by space craft.

The insight from Sudbury is complemental, the geologists say, because you can directly observe the rocks with your own eyes and collect loads of samples for detailed study in the lab.

More information: Teresa Ubide et al, Protracted volcanism after large impacts: Evidence from the Sudbury impact basin, Journal of Geophysical Research: Planets (2017). DOI: 10.1002/2016JE005085

Original article here.

Planetary Defense Conference (PDC) 2017 – Day 5

Friday, May 19, 2017, Tokyo, Japan

The last day of the PDC was fully dedicated to the hypothetical NEO/Earth impact event scenario exercise.

During the whole week the experts worked on this exercise that aims to deflect the fictitious asteroid 2017 PDC.

planetary defense conference pdc 2017 day 5

Orbit of Asteroid 2017 PDC

The initial scenario was as follows:

  • An asteroid is discovered on March 6, 2017, at magnitude 21.1, and confirmed the following day. It is assigned the designation “2017 PDC” by the Minor Planet Center.
  • Initial calculations indicate that 2017 PDC’s orbit approaches well within 0.05 au to that of the Earth, and it is therefore classified as a Potentially Hazardous Asteroid (PHA). The orbit is eccentric, extending from a distance of 0.88 au from the Sun at its closest point to 3.60 au at its farthest point. The asteroid’s orbital period is 1225 days (3.35 years), and its orbital plane is inclined 6.3 degrees to the orbit of the Earth.
  • The day after 2017 PDC is discovered, JPL’s Sentry impact monitoring system, along with ESA’s similar CLOMON system, both identify several future dates when this asteroid could potentially impact the Earth. The date of the most likely potential impact is July 21, 2027 – over ten years away – but the probability of impact is very low, about 1 chance in 40,000.
  • When first detected, the asteroid is about 0.36 au (54 million kilometers or 33 million miles) from Earth, approaching our planet and getting brighter. It is observed extensively, and as the observational dataset grows, the impact probability for 2027 increases. The asteroid peaks in brightness at magnitude 20.4 on April 7, by which time the impact probability has risen to nearly 0.2 percent.
  • Very little is known about the asteroid’s physical properties. Based on the apparent visual magnitude, its absolute (intrinsic) magnitude is estimated to be about H = 21.9 +/- 0.4. But since its albedo (reflectivity) is unknown, the asteroid’s mean size could be anywhere from 100 meters to over 250 meters.
  • 2017 PDC approaches the Earth for well over a month after discovery, and it reaches its closest point of about 0.13 au in late April. Unfortunately, that is too far to be detected by Goldstone radar, and too far south for Arecibo radar. The asteroid is not expected to pass close to the Earth again, until the potential impact in 2027.
  • Observers track the asteroid almost daily since discovery, and the impact probability for 2027 continues to rise. As of May 15, 2017, the probability of impact has reached about 1%.

Every day new information and guidelines were introduced, in order to create an exercise as close to a real situation as possible.

Important to mention that the whole exercise is completely fictional and does NOT describe an actual potential asteroid impact.

You can find all the detailed information about the exercise, including the final results, here.

 

The PDC comes to an end. It was a great event, bringing together experts from all over the world to discuss the threat to Earth posed by asteroids and comets and actions that might be taken to deflect a threatening object.

It is very inspiring to see people from different cultures, backgrounds and speaking different languages, coming all together to discuss about a common threat to all of us.

The Planetary Defense Conferences are extremely important and the NEOShield-2 team could not be prouder of participating in it and contributing to protect Earth from the next major asteroid impact.

planetary defense conference pdc 2017 day 5

From left to right:
Martin Schimmerohn (Fraunhofer EMI), Kilian Engel (Airbus DS), Siegfried Eggl (NASA/JPL), Line Drube (DLR), Daniel Hestroffer (OBSPM), Albert Falke (Airbus DS), Simon Delchambre (Airbus DS) and Alan Harris (DLR).

 

You can watch all speeches and the exercise here.

Check the full list of the NEOShield-2 participation here.

Check also Day 1, Day 2, Day 3 and Day 4.

Planetary Defense Conference (PDC) 2017 – Day 4

Thursday, May 18, 2017, Tokyo, Japan

The penultimate day of the PDC started with the speeches of the Session 6, which addressed the topic Impact Consequences, where experts explained what would happen if an asteroid would impact Earth.

Still in the morning, the Session 7 took place with speeches about Disaster Response, presenting ways to respond to the impact threat once it becomes real.

The afternoon started with the Session 8, addressing Impact Risk Assessment and Decision to act. ESA and NASA shared very interesting information about Planetary Defense.

Closing the day, the Session 9 approached a very important topic: Public Education & Communication, which raises the importance of educating and communicating about the asteroid threat impact.

Day 4 closes the speeches. There were more than 80 speeches given by experts from all over the world. The speeches were complemented by almost 100 posters, providing valuable information about the scientific and industrial work that has been done regarding planetary defense.

planetary defense conference pdc 2017 day 4

PDC Group Photo. Credit: IAA

What to expect on Day 5 (last day):

The whole day will be dedicated to the threat response exercise (Session 10).

Check more details about the exercise here.

 

Check also Day 1, Day 2 and Day 3.

Check the full list of the NEOShield-2 participation here.

Check the whole PDC program here.

You can stream live or check later all the speeches here.

Planetary Defense Conference (PDC) 2017 – Day 3

Wednesday, May 17, 2017, Tokyo, Japan

The third day of the PDC was the day that the NEOShield-2 team participated most.

The day started with the continuation of the Session 4, initiated on the previous day. Later on, the Session 5 got started with the topic Mission & Campaign designs.

The first speeches in this session addressed the Asteroid Impact And Deflection Assessment (AIDA), the NASA’s Double Asteroid Redirection Test (DART) Mission and the ESA’s Asteroid Impact Mission (AIM). On this topic, Patrick Michel from CNRS and NEOShield-2, gave a speech about Performing Binary Asteroid Investigation and Supporting Planetary Defense on the AIM. Besides his contributions to NEOShield-2, Patrick also performs researches for the AIDA mission together with the Observatoire de la Côte d´Azur (OCA).

In the afternoon, Albert Falke, from Airbus DS Germany, representing the coordination of the NEOShield-2 project, presented the project overview and its achievements so far.

pdc 2017 day 3

Albert Falke

Following Albert’s speech, Line Drube, from DLR, introduced the NEOTωIST mission concept, which is a relatively inexpensive Kinetic Impactor demonstration mission concept proposed by the NEOShield-2 project.

pdc 2017 day 3

Line Drube

Complementing Line’s speech, Kilian Engel, from Airbus DS Germany, explained how the NEOTωIST mission should be designed featuring NEO spin change and observer sub-spacecraft.

pdc 2017 day 3

Kilian Engel

Still related to the Session 5, NEOShield-2 team participated with 4 posters:

  • NEOShield-2: Design and End-to-End Validation of an Autonomous Closed-Loop GNC System for Asteroid Kinetic Impactor Missions by Marc Chapuy, Airbus DS Toulouse
  • Keyhole Maps for Post Deflection Impact Risk Assessment by Siegfried Eggl, previous Observatoire de Paris, now NASA/JPL-Caltech
  • NEOTωIST: Determining the Momentum Enhancement by Siegfried Eggl, previous Observatoire de Paris, now NASA/JPL-Caltech
  • NEOShield-2: Optical Navigation for Near-Inertial Hovering at Close Proximity of Very Small Asteroids by Simon Delchambre, Airbus DS Germany

Marc Chapuy and his poster

pdc 2017 day 3

Albert Falke and Siegfried Eggl

pdc 2017 day 3

Simon Delchambre and his poster

Closing the day, more guidelines were given regarding the hypothetical NEO/Earth impact event scenario. You can check them here.

The NEOShield-2 team ends its participation in the PDC 2017. That was a great opportunity for the team to present the significantly work they have been doing to protect Earth from the next major asteroid impact.

What to expect on Day 4:

Speeches about:

  • Impact Consequences (Session 6)
  • Disaster Response (Session 7)
  • Impact Risk Assessment & Decision to Act (Session 8)
  • Public Education & Communication (Session 9)

 

Check also Day 1 and Day 2.

Check the full list of the NEOShield-2 participation here.

Check the whole PDC program here.

You can stream live or check later all the speeches here.