The known unknowns – the outstanding 49 questions in Earth sciences (Part I)

5 Sep

The Northern Hemisphere (Credit: Maximilian Reuter,

The Northern Hemisphere
(Credit: Maximilian Reuter, via

Science is about asking questions, as much as it is about finding answers. Most of the time spent by scientists doing research is used to constrain and clarify what exactly is unknown – what does not yet form part of the consensus among the scientific community. Researchers all over the globe are working tirelessly to answer the unresolved questions about the inner workings of our planet, but inevitably new answers only lead to new questions. What are the main questions that will keep Earth scientists busy for many years to come?

Daniel Garcia-Castellanos (working at the Spanish National Research Council [CSIC] in Barcelona), through online collaboration with other colleagues, has put together a list of the top 49 questions which provide a fully referenced account of the main current scientific questions, disputes and challenges in the geosciences, with special emphasis on the solid Earth. Nevertheless, 49 is a big number, so we’ve split the questions into more manageable sections. What follows is a series of five posts over the next few weeks, detailing key research questions in specific areas.

This series should be your one-stop shop and quick-reference guide of the current hot topics in geosciences. If you are a budding investigator, let it serve as inspiration for the direction you want your research to take and, if you are an established scientist, let it reignite your passion for the subject. For everyone else, marvel at everything we’ve yet to learn. If you think there are other questions that should be added to the list, we’d love to hear from you! Make sure you add your suggestions in the comments section.

We start the series with the fundamental question: How did it all begin?

The Early Earth and the Solar System

New, exciting hypotheses about the early stages of our planet have been driven by advances in our understating of the geochemistry of meteorites, amongst other findings. As per usual, the answers are outnumbered by our numerous knowledge gaps:

1. How did the Earth and other planets form? Were planets formed in situ or in orbits different from their present ones? What determined the different deep layering of the solar planets? (McKinnon, 2012, Science – on Mercury)

2. How did the Moon form? Was there ever a collision of the Earth with another planet (Theia), which might have given birth to our satellite? (Canup, 2013, Science) There is compelling evidence, such as measures of a shorter duration of the Earth’s rotation and lunar month in the past, pointing to a Moon much closer to Earth during the early stages of the Solar System. (Williams, 1991, CSPG Spec. Pubs.)

The Moon. (Credit: Konstantinos Kourtidis, via

The Moon (Credit: Konstantinos Kourtidis, distributed via

3. How hot is the inside of the planet and how did this temperature evolve? How did Earth’s internal temperature decay since it formed by accretion of stony meteorites known as chondrites? How abundant are radiogenic elements in the Earth’s interior and to what extent are they a source of internal heat? Did a “faint young sun” ever warm a “snowball Earth”? (WiredMarty et al., 2013, Science)

4. Why do plate tectonics occur only on Earth? (Martin et al., 2008, Phys. Edu.) How did the planet cool down before the mantle convection lead to plate tectonics? Was the Earth’s crust formed during the early stages of its evolution or is it the result of a gradual distillation of the mantle that continues today along with crustal recycling? Is the crust still growing or does its recycling compensate for crust formation at mid-ocean ridges and other volcanic areas?


Plate tectonic map (Source: Wikimedia Commons, Credit: NASA)

5. How inherent to planetary evolution is the development of life conditions? Earth-like planets are now known to be abundant in our galaxy (two out of three stars may have one [for example, Cassan et al., 2012, Nature]), but how many of them develop widespread durable water chemistry? (Zimmer, 2005, ScienceElkins-Tanton, 2013, Nature) How much of our water is supplied by comets or asteroids; when and how did it reach the Earth? [Greene, 2013, Smithsonian Mag.]

Water Drops. (Credit: Jacqueline Isabella Gisen, via

Water drops (Credit: Jacqueline Isabella Gisen, via

Whilst this is likely not an exhaustive list of the questions we have about how our planet came to be and its early development, it no doubt highlights the frontiers of our current understanding.

Next time we explore the Earth’s deep interior. Direct study of samples can only be achieved for the top 12km of the Earth’s crust, so what lies beneath?


By Laura Roberts Artal, EGU Communications Officer, based on the article previously posted on RetosTerricolas by Daniel Garcia Castellanos, researcher at ICTJA-CSIC, Barcelona

Shape the scientific programme at the EGU 2015 General Assembly

4 Sep

Time is running out, so if you have a great idea for a conference session but haven’t quite put it into practice: now’s your chance!

Until this time next week (12th September) you can submit your session ideas and take part in organising the scientific programme for the EGU General Assembly in 2015.

What you need to do:

  1. Take a look at the sessions that have already been suggested within the Programme Group tab in the website - where does your idea fit in?
  2. Suggest a convenor for the session and provide a short description, outlining what the session will cover
  3. Suggest modifications to the skeleton programme
  4. Submit your ideas!

You can make session suggestions and find out more on the EGU 2015 website.

Outside the conference centre during EGU 2014

Outside the conference centre during EGU 2014

GeoCinema Online: Our changing Climate

3 Sep

Welcome to the third instalment of Geocinema! The focus this week is on climate change and how it impacts on local communities. Sit back, relax and make sure you’ve got a big bucket of popcorn on the go, as this post features a selection of short documentaries as well as trailers of feature length films.

Documenting the effects of the warming conditions on the surface of our planet is the primary focus of many researchers but understanding how these changes directly affect communities is just as important. The two are intrinsically linked and the films this week  highlight just to what extent this is true.

Thin Ice

In this feature film, a global community of researchers, from the University of Oxford and the Victoria University of Wellington, race to understand the science behind global warming and our planet’s changing climate.

Find detailed information of the project here.


High Mountain Glacial Watershed Program

How are communities in mountainous regions affected by significant watershed? In the film, scientist try to find a way to better manage these events.


The wisdom to Survive

What are the challenges of adapting to an ever changing climate? The film explores how we can adjusts to living in the wake of this significant challenge through talking to leaders in the realms of science, economics and spirituality.


Glacial Balance

Humans have depended on supplies of water since the dawn of mankind.  Ever changing weather patterns means supplies of water are shifting and communities are having to relocate to access fresh provisions. Glacial Balance takes us on a journey from Colombia to Argentina, getting to know those who are affected by melting glacial reserves in the Andes.


Enjoyed the series so far? There are more films you can catch up on here and here.

We will explore further facets of our ever changing planet in the next instalment of GeoCinema, stay tuned to the blog for more posts!


Thin Ice: Keith Suez,

High Mountain Glacial Watershed Program : Daniel Byers,

The Wisdom to Survive: Gwendolyn Alston,

Glacial Balance: Ethan Steinman,

Imaggeo on Mondays: A massive slump

1 Sep

One of the regions that has experienced most warming over the second half of the 20th century is the Potter Peninsula on King George Island in Antartica. It is here that Marc Oliva and his collaborators are studying what the effects of the warming conditions on the geomorphological processes prevailing in these environments.

“Permafrost is present almost down to sea level in the South Shetland Islands, in Maritime Antarctica” says Marc, “in some recent deglaciated environments in this archipelago, the presence of permafrost favours very active paraglacial processes”.

Permafrost is defined as the ground that remains frozen for periods longer than two consecutive years and constitutes a key component of the Cryosphere. However, it is not fully understood how it reacts to climate variability. In this sense, there is an on-going effort to improve our knowledge on these topics by carrying out long–term monitoring of permafrost, as well as of geomorphological processes, in order to better understand the response of the terrestrial ecosystems to recent warming trends.

This weeks’ Imaggeo on Mondays picture shows a massive slump and the exposed permafrost in the shoreline of a lake in Potter Peninsula (King George Island, Maritime Antarctica). Following the deglaciation of this ice-free area paraglacial processes are very active transferring unconsolidated sediments down-slope to the lake.

Slump-permafrost, Potter Peninsula, Antarctica. (Credit: Marc Oliva via

Slump-permafrost, Potter Peninsula, Antarctica. (Credit: Marc Oliva via

Imaggeo is the EGU’s open access geosciences image repository. Photos uploaded to Imaggeo can be used by scientists, the press and the public provided the original author is credited. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. You can submit your photos here.


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