Journal Entry

Astronomy Night

I had a wonderful time as a guest teacher for an evening astronomy class at Georgia Gwinnett College. Thank you, Georgia Gwinnett for having me and giving me the opportunity to talk about one of my favorite topics- our solar system! The lesson focus was on the gas giants, Jupiter, Saturn, Uranus and Neptune. Fun fact: On April 4th, the Cassini mission confirmed a regional ocean at the south pole of Encelades, a moon of Saturn, through measurements that revealed a gravity anomaly. The south pole is more dense than expected. Explanation= liquid water. (Liquid water is more dense than ice.) The ocean's interaction with the moon's rocky core could generate the chemical reactions and nutrients necessary for the evolution of life. Very cool.

Talking about Europa with students at Georgia Gwinnett CollegeTalking about Europa with students at Georgia Gwinnett College

High Arctic Change 2014

I shared the upcoming expedition and how GGC students can become involved. A great conversation and interesting questions followed.

Introducing High Arctic Change 2014Introducing High Arctic Change 2014

Gravity Corer

John asked a great question about a picture I shared from the 2011 expedition showing use of the gravity corer: "What drives the gravity corer through sediment that deep?"

Operating the gravity corer in 2011. Photo courtesy of Mark Goldner.Operating the gravity corer in 2011. Photo courtesy of Mark Goldner.

The answer is in the name- gravity! The corer is weighted and well over 40 pounds. It falls under its own weight, using gravity to penetrate the soft sediment. The corer has an inner plastic liner that houses the sediment within the metal barrel and a core catcher to minimize sample loss. But the weights that help drive the corer into the sediment also make it difficult to pull the corer back up. A winch is used, but it still has to be lifted overhead in order to separate the sample from the device.

Gravity corer. Photo courtesy of U.S. Geological Service.Gravity corer. Photo courtesy of U.S. Geological Service.

All of this work is done to collect a sediment core like the one shown below. Back at the lab the plastic liner and core is split down the middle and opened. Cores capture a time capsule that can span the past thousands of years. Through analysis of the layers and their content, we can improve understanding of past climate systems and predict patterns for the future. Thanks for the great question!

Sample sediment core. Photo courtesy of International Atomic Energy Agency.Sample sediment core. Photo courtesy of International Atomic Energy Agency.

Comments

Mon, 04/28/2014 - 09:11

Peggy McNeal

Junior and Alicia,Great question (and a very complicated one).
Scientists take tons and tons of data that has been collected world wide on things like weather patterns, chemical composition of the atmosphere, composition of ice sheets, ground sediment, etc., etc., etc. and create computer programs that compare this data to past climates and then model what it might be like in the future based on the data.

Mon, 04/21/2014 - 10:05

Guest

This is Kiyahna and Alexa from per.2.How do you analyze the sediment to find out past and future climate patterns?

Mon, 04/21/2014 - 10:07

Guest

This is Myranda and Darcy from period 2. How do scientists understand past climate systems and predict patterns for the future?

Mon, 04/21/2014 - 10:07

Guest

This is Myranda and Darcy from period 2. How do scientists understand past climate systems and predict patterns for the future?

Mon, 04/21/2014 - 10:10

Guest

When,who, and why was the gravity corer made and how it's used?

Mon, 04/21/2014 - 10:10

Guest

When,who, and why was the gravity corer made and how it's used?

Mon, 04/21/2014 - 10:10

Guest

This is Chloe and Kelsey from period 2.How do you predict future weather from the sediment out of the gravity corer?

Mon, 04/21/2014 - 10:10

Guest

what is the average tempeture of the corer? how hot can it get and how cold can it get?

Mon, 04/21/2014 - 10:10

Guest

what is the average tempeture of the corer? how hot can it get and how cold can it get?

Mon, 04/21/2014 - 10:10

Guest

what is the average tempeture of the corer? how hot can it get and how cold can it get?

Thu, 04/24/2014 - 07:26

Peggy McNeal

Kiyahna and Alexa,There are a few ways to do this.  I'll give you one example.  Lets say that within some of the sediment is found some ancient pollen grains.  Scientists can get an idea of what kind of plants were growing during that time from these preserved pollen grains.  Because plants grow in an environment that can sustain them, knowing what plants were growing in the past tells us if the climate was wet, dry, warm, or cold.  By analyzing trends from the past, scientists are able to make some predictions about the future.

Thu, 04/24/2014 - 07:41

Peggy McNeal

Myranda and Darcy,Great question!  I think I answered your question in my response to Kiyahna and Alexa.  Check it out and let me know if you want to know more.

Thu, 04/24/2014 - 07:41

Peggy McNeal

The gravity corer allows researchers to sample and study sediment layers at the bottom of lakes or oceans. The first real oceanographic research was done 1872-1876 on the Challenger Expedition.  Many of the sampling techniques and instrumentation that are still used today were developed and used at that time.

Thu, 04/24/2014 - 07:56

Peggy McNeal

Hello Chloe and Kelsey,First I need to make a distinction between weather and climate.  Weather is what is going to happen on any given day.  For example, today it is going to be sunny.  Sediment samples can't tell us anything about the weather.  Climate describes long term averages, for example San Diego has a semi-arid climate.  Sediment cores can tell us something about climate by analyzing whats in the sediment.  Ash, dust, and pollen found among the layers can tell of other environmental conditions in the past- was it warm, wet, cold, dry?  By analyzing past trends, scientists can compare to current trends and make some predictions about the future.

Thu, 04/24/2014 - 07:56

Peggy McNeal

Regarding average temperature of the corer- I'm not sure I understand the question.  The corer is the instrument used to obtain the sediment sample.  I think you are asking about the temperature of the sample core?  In the case of the samples that we might obtain, they are really surface samples and don't go all that deep.  Maybe a few meters.  So they reflect the environmental temperature, in this case the temperature of the water- right around freezing.

Fri, 04/25/2014 - 10:07

Guest

This is Junior Yono and Alicia Estrada from period 2. How did scientists figure out how climate systems work? And how do they predict patterns?

Fri, 04/25/2014 - 10:07

Guest

This is Junior Yono and Alicia Estrada from period 2. How did scientists figure out how climate systems work? And how do they predict patterns?