ROCKY REX'S SCIENCE BITES

When the Sun's energy arrives at the Earth, it travels through the air. Some is reflected back to space, but some hits the Earth and warms it. The warm Earth gives off  infrared radiation  with various wavelengths.   Some of those waves can pass back out of the air to space, but some are absorbed by certain gases in the air. The gases then give off the waves into the air. If there are more of those gases, less heat escapes into space. An extreme case has happened on Venus. Concentrated  'greenhouse gases'  on Venus have caused the surface temperature to rise to 735  Kelvin  (462 degrees C; around 900 degrees F) Carbon dioxide levels in the atmosphere have risen quickly  since people began burning large quantities of fossil fuels. There was carbon dioxide in the air before that, at around 270 parts per million. Without any carbon dioxide, the Earth would be very cold. The temperature would be around -1...

Carbon dioxide levels in the atmosphere are rising. This graph showing the data is called the Keeling Curve. It is named after the scientist who first produced accurate measurements of carbon dioxide in the air -  Charles David Keeling.    Keeling's data began in 1958. What about carbon dioxide levels before 1958? That information has been found by drilling into the ice in places like Antarctica and Greenland. As layers of ice build up, they trap bubbles of air, which hold the evidence of the atmosphere from the year the layer was formed. Law Dome is a location in Antarctica. The evidence shows that since around the late 18th century, as the Industrial Revolution began, carbon dioxide levels have risen. They had changed from around 280 parts per million to over 300 ppm when Keeling began his records in 1958. Now it has reached around 400 ppm in just around 50 years. This is a very fast rise, compared to the past.

Meteorites are objects from space that have reached the surface of the Earth. Before they hit the ground they are seen as meteors. Most meteors burn up completely, but some survive - some amazing videos were taken of a meteor event in February 2013 in Russia.  Meteorites are generally of three main types Iron               Stony-Iron             Stony One of the best places to find meteorites is  Antarctica ,  because the dark meteorites stand out against ice. Professor Sara Russell from the Natural History Museum in London has been to Antarctica to collect meteorites.                                       

The phrase 'ocean acidification' is used to mean that the pH of seawater is reducing. The pH scale is used by scientists to describe strength of acids and alkalis.  Sea water normally had a pH around 8.3 but it has now reduced to 8.1 and will continue to reduce as more CO 2  is added to the air by human activities. Some of the extra CO 2  in the air dissolves in the sea, and this affects sealife. Here is what one expert scientist has said about this - Surface ocean pH has fallen by about 0.1 pH unit from preindustrial times to today  — a 0.1-unit pH drop is equivalent to about a 26% increase i n the ocean hydrogen ion concentration. pH is likely to drop by 0.3-0.4 units by the end of the 21st century, and increase ocean hydrogen ion concentration (or acidity) by 100-150% above what it was in preindustrial times. —  Scott Doney, Senior Scientist, Woods Hole Oceanographic Institution, USA       Humanity's greenhouse gas emiss...

Astronauts' bootprints on the Moon will stay fresh for a long time. No rain, no wind will disturb these imprints. Amazingly, footprints of other kinds of creatures have survived on the Earth. This can be because they were quickly covered by volcanic ash, or other layers of fine material, preserving the details. These footprints were most likely made by Australopithecus afarensis , an early human whose fossils were found in the same sediment layer. They were found at Laetoli in Tanzania. The Smithsonian Museum has a wonderful site about footprints found at Laetoli. Looking at much older rocks, footprints of dinosaurs can be used to find out all sorts of things about their lives. There are plenty of dinosaur tracks in Texas, for example . Working out the meaning of dinosaur footprints can be a great example of using scientific thinking. The  MEETING OF THE DINOSAURS  is a wonderful activity for anyone who likes dinosaurs.  

It’s actually a little easier to look at the impact of fossil fuels using coal as an example, but the principle applies to all fossil fuels. A typical three-metre (10-foot) coal seam is estimated to have taken between 12,000 and 60,000 years to form . Ancient trees and plants lived, died and were fossilised, having used carbon dioxide from the atmosphere over those millennia. Some larger coal seams are, for example, 10 metres thick. They took around 40,000 years to form but have been mined and burned in a little over 100 years. We are time-warping vast amounts of ancient carbon (which we are combining with current oxygen) into our modern atmosphere. Currently natural processes are absorbing about 50% of the (around) 35 billion tonnes of CO2 produced annually by human activities. The figure of 33.4 billion metric tonnes is for for 2010.  The figure for 2014 is expected to be 40 billion metric tonnes.  The fastest rise of CO 2  in the air seen in ...

The Orion Nebula is a fuzzy area among the stars of Orion's sword, which is seen below the three Belt Stars. To the naked eye, it looks like a star in the sword. With binoculars or a telescope, it is actually a large glowing cloud of material.  This nebula  is about 1630 light years away.  Many newborn stars shine on the gas cloud that they collapsed from. This makes the gas glow.

The Earth is warming because humans are producing lots of carbon dioxide. Without that, the Earth would be cooling towards a new 'ice age' - a glacial stage, to use the better term. We know this because most of the things that cause glacial stages are regular patterns of movement by the Earth as it orbits the Sun. The ice would start to return in around 1,500 years, but only if there was a lot less carbon dioxide in the air. So is it a good thing that a lot of carbon dioxide is being made? No.... the CO 2  needed to hold back the ice was made by simple things like farming long before the Industrial Revolution. The huge amount made over the last 150 years has taken things to a different situation, where very fast warming is happening. This is going to change all kinds of things. Atmospheric CO2 is now just below 400 parts per million (ppm) on average. That has not happened since the Pliocene (5.3-2.6 million years ago). At that time, temperatures rose to leve...

The constellation of Orion dominates the southern sky during winter in the Northern Hemisphere. The brightest stars of Orion have wonderful names. The Red Giant star Betelgeuse marks one shoulder, the other shoulder is marked by Bellatrix. The three Belt Stars (left to right) are Alnitak, Alnilam and Mintaka. The knees are marked by Saiph and the very bright Rigel. Like many star names they are of Arabic origin . The stars of Orion act as signposts to other stars seen at the same time of year. Stars shown here are good examples of some of the variety of types of stars.   The Sun is really rather small compared to many stars

Lots of people discuss 'climate change' but what does the word 'climate' mean? Folks forget how climate is defined..... Climate  is normally defined as 'an average over 3 conventional decades'. A conventional decade is, for example, 2001-2010, or 1961-1970. So ..... 3 full, conventional decades......such as 1981 to 2010. For example .... rainfall in Ireland. And another example -  ' Average temperature 1951-1980 ' The definition of 'climate' goes back at least 100 years. So if we are discussing climate change, that is what 'climate' means. But in recent times, there has been a lot of variation in global temperatures. So it can be useful to look at single conventional decades. Data from the World Meteorological Organisation.

Space is not very far away. Aircraft on long-haul flights travel at a height of about 10 km. The Troposphere ends at about 15 km, and the air in the upper atmosphere is very thin indeed. Think of a place around 15 km (9 miles) from where you are. That's pretty much how near you are to space. All the waste gases dumped into the air are basically trapped in the thin layer of air around the Earth.

There are very many websites with opinions on climate change. Where is there something we can trust? Let's see what long-established scientific organisations tell us. The Royal Society  has been the home of science in the UK since the 1660s, and Sir Isaac Newton was a President of the Royal Society in its early days. Coat of Arms of the Royal Society What do they say now about climate change? Scientists know that recent climate change is largely caused by human activities from an  understanding of basic physics, comparing observations with models, and fingerprinting  the detailed patterns of climate change caused by different human and natural influences.  The speed of the current climate change is faster than most of  the past events, making it more difficult for human societies and the natural world to adapt.  Climate Change: Evidence and Causes Which was put together by the Royal Society and the National Academy of Sciences, their equival...

Only about 29% of the Earth is above sea level, so perhaps it should be called 'Water' or 'Ocean'? For most of human history, almost nothing was known about the deep oceans. The science of the oceans - Oceanography - is still full of chances to discover new things. The deeper you go, the darker it gets, and most of the deep ocean never sees any sunlight. To get a sense of the excitement of oceanography.. These oceanographers give a hint of their work.

Healthy coral can be very colourful. Some coral reefs recently have started to look rather different. This is called 'coral bleaching'. To understand this, we need to start by looking at corals. Corals are animals that make a framework around them  that looks like rock. Coral animals (polyps) have tiny  plants - algae - living in their tissues. The algae provide food to the corals, which they produce by photosynthesis. Corals only live in a limited temperature range. Like porridge, they need to be not too hot and not too cold. Coral reefs  are concentrated in a band around the equator, between 30 ° N and 30 ° S latitude. Corals grow in warm shallow waters that receive plenty of light. Most corals grow in the warmest water they can stand (about 85° F or 29° C).  This means that slight increases in ocean temperature can harm corals. High sea temperature is the main reason for coral bleaching.

The name means 'wing-finger' . Bird wings are supported on 'arm bones'. The outer part of bat wings are supported on finger bones. The outer part of the wings of pterodactyls and other   pterosaurs   are supported on long 'little finger' bones. One well-known larger pterosaur is Pteranodon.

Geologists have discovered five major mass extinction  events in the rock record of the last 600 million years. The extinction at the end of the Permian period, around 252 million years ago, was the most extreme. It is called the  End-Permian mass extinction . Only about 8% of species survived to live on in the Triassic Period. This photo shows tilted sedimentary rocks at Shangsi in South China, with Triassic rocks at the top right overlying the older Permian rocks. Each mass extinction in the rocks matches with a change in the chemistry of the rocks called a ' carbon excursion '. Some of the carbon excursions are 'negative' and some are 'positive'. Negative CEs involve lots of gaseous carbon compounds adding to the air, causing warming. Positive CEs involve the reverse.... processes absorb the gases and cooling follows. Examples of positive CEs include   The 'Snowball Earth'   events. An example of a negative...

Fossils from the Devonian ‘Age of Fishes’ are found across Scotland.  They lived in a time when life flourished in rivers and lakes.  In the Devonian period, 417 to 354 million years ago, Scotland lay south of the equator.   Fish had evolved in the sea, but by Devonian times they also lived in rivers and lakes. The Devonian rocks in which these fossils are found is often called the "Old Red Sandstone", seen here in south-east Scotland.

Agriculture needs nice predictable conditions.  Farmers can put up with some bad weather, but climate change will make unusual events more likely. 20-30% of plant and animal species will be more likely to become extinct if the temperature rises by more than 1.5-2.5C. There will be big effects on farming from droughts and floods. The biggest effects will be seen first near the equator. Just being near the equator makes it more difficult for countries to make economic progress. Hotter conditions affect how crops grow. Our agriculture is heavily reliant on grasses from the temperate regions. Corn, wheat, rice and so on are all types of grass. The tropics is a hard place to grow an industrial society. The tropics will expand as the world warms, so the world will find it harder to grow those important crops.

Jupiter is the biggest object orbiting the Sun. Jupiter is mainly composed of gases, mostly hydrogen and helium.  In this image, Jupiter's moon  Io   is the 'bead' just above the Great Red Spot. The Great Red Spot is bigger than Earth. Studies have indicated that the Great Red Spot is travelling around the planet. The Great Red Spot is a storm bigger than Earth, and has been seen since Jupiter was first examined through telescopes hundreds of years ago. It appears to be shrinking.

Most people think climate change always happens slowly, but that is wrong. Rapid climate change was discovered by accident by Russell Coope. In the 1950s, Russell Coope was a young geologist who spotted something unusual in a quarry in the English Midlands.  This is his own description of what he found ... "I happened, entirely by accident, to visit a Quaternary gravel pit in which were exposed the spectacular bones of mammoth, woolly rhinoceros and bison.  Looking at their sediment matrix I was amazed to find enormous numbers of equally spectacular, if somewhat smaller, insect remains.  I was hooked instantly!  Particularly exciting to me was the fact that these insect fossils showed that Quaternary climates had changed abruptly.  Thus, at times, fully glacial climates gave place to temperate interglacial conditions within the span of one human lifetime." This discovery was the first time it had been realised that the climate can change really quic...