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Yes, the climate has always changed. This shows why that’s no comfort.

By Brad Plumer, vox.com Jan 13, 2017

Randall Munroe, the author of the webcomic XKCD, has a habit of making wonderfully lucid infographics on otherwise difficult scientific topics. Everyone should check his take on global warming. It’s a stunning graphic showing Earth’s recent climate history. Take some time with it. Stroll through the events like the domestication of dogs and the construction of Stonehenge. And then ponder the upshot here.

There’s a common line among climate skeptics that “[t]he climate has always changed, so why worry if it’s changing now?” The first half of that sentence is undeniably true. Due to orbital wobbles, volcanic activity, rock weathering, and changes in solar activity, the Earth’s temperature has waxed and waned over the past 4.5 billion years. During the Paleocene it was so warm that crocodiles swam above the Arctic Circle. And 20,000 years ago it was cold enough that multi-kilometer-thick glaciers covered Montreal.

But Munroe’s comic below hits at the “why worry.” What’s most relevant to us humans, living in the present day, is that the climate has been remarkably stable for the past 12,000 years. That period encompasses all of human civilization — from the pyramids to the Industrial Revolution to Facebook and beyond. We’ve benefited greatly from that stability. It’s allowed us to build farms and coastal cities and thrive without worrying about overly wild fluctuations in the climate.

And now we’re losing that stable climate. Thanks to the burning of fossil fuels and land use changes, the Earth is heating up at the fastest rate in millions of years, a pace that could prove difficult to adapt to. Sea level rise, heat waves, droughts, and floods threaten to make many of our habitats and infrastructure obsolete. Given that, it’s hardly a comfort to know that things were much, much hotter when dinosaurs roamed the Earth.

XKCD A timeline of Earth's average history

Randall Munroe



Astronomy Learning Standards

Learning standards for astronomy, and related parts of Earth Science.


Massachusetts Curriculum Frameworks Science and Technology/Engineering (2016) 

6.MS-ESS1-1a. Develop and use a model of the Earth-Sun-Moon system to explain the causes of lunar phases and eclipses of the Sun and Moon.

6.MS-ESS1-5(MA). Use graphical displays to illustrate that Earth and its solar system are one of many in the Milky Way galaxy, which is one of billions of galaxies in the universe.

8.MS-ESS1-1b. Develop and use a model of the Earth-Sun system to explain the cyclical pattern of seasons, which includes Earth’s tilt and differential intensity of sunlight on
different areas of Earth across the year

8.MS-ESS1-2. Explain the role of gravity in ocean tides, the orbital motions of planets, their moons, and asteroids in the solar system

HS-ESS1-1. Use informational text to explain that the life span of the Sun over approximately 10 billion years is a function of nuclear fusion in its core. Communicate that stars, through nuclear fusion over their life cycle, produce elements from helium to iron and release energy that eventually reaches Earth in the form of radiation.

HS-ESS1-2. Describe the astronomical evidence for the Big Bang theory, including the red shift of light from the motion of distant galaxies as an indication that the universe is currently expanding, the cosmic microwave background as the remnant radiation from the Big Bang, and the observed composition of ordinary matter of the universe, primarily found in stars and interstellar gases, which matches that predicted by the Big Bang theory (3/4 hydrogen and 1/4 helium).

HS-ESS1-4. Use Kepler’s laws to predict the motion of orbiting objects in the solar system.
Describe how orbits may change due to the gravitational effects from, or collisions
with, other objects in the solar system. Kepler’s laws apply to human-made satellites as well as planets, moons, and other objects.


A Framework for Science Education

A Framework for K-12 Science Education: Practices, Crosscutting Concepts, and Core Ideas (2012)

Stars’ radiation of visible light and other forms of energy can be measured and studied to develop explanations about the formation, age, and composition of the universe. Stars go through a sequence of developmental stages—they are formed; evolve in size, mass, and brightness; and eventually burn out. Material from earlier stars that exploded as supernovas is recycled to form younger stars and their planetary systems. The sun is a medium-sized star about halfway through its predicted life span of about 10 billion years.

Grade Band Endpoints for ESS1.A

By the end of grade 2. Patterns of the motion of the sun, moon, and stars in the sky can be observed, described, and predicted. At night one can see the light coming from many stars with the naked eye, but telescopes make it possible to see many more and to observe them and the moon and planets in greater detail.

By the end of grade 5. The sun is a star that appears larger and brighter than other stars because it is closer. Stars range greatly in their size and distance from Earth.

By the end of grade 8. Patterns of the apparent motion of the sun, the moon, and stars in the sky can be observed, described, predicted, and explained with models. The universe began with a period of extreme and rapid expansion known as the Big Bang. Earth and its solar system are part of the Milky Way galaxy, which is one of many galaxies in the universe.

By the end of grade 12. The star called the sun is changing and will burn out over a life span of approximately 10 billion years. The sun is just one of more than 200 billion stars in the Milky Way galaxy, and the Milky Way is just one of hundreds of billions of galaxies in the universe. The study of stars’ light spectra and brightness is used to identify compositional elements of stars, their movements, and their distances from Earth.

Grade Band Endpoints for ESS1.B

By the end of grade 2. Seasonal patterns of sunrise and sunset can be observed, described, and predicted.

By the end of grade 5. The orbits of Earth around the sun and of the moon around Earth, together with the rotation of Earth about an axis between its North and South poles, cause observable patterns. These include day and night; daily and seasonal changes in the length and direction of shadows; phases of the moon; and different positions of the sun, moon, and stars at different times of the day, month, and year.

Some objects in the solar system can be seen with the naked eye. Planets in the night sky change positions and are not always visible from Earth as they orbit the sun. Stars appear in patterns called constellations, which can be used for navigation and appear to move together across the sky because of Earth’s rotation.

By the end of grade 8. The solar system consists of the sun and a collection of objects, including planets, their moons, and asteroids that are held in orbit around the sun by its gravitational pull on them. This model of the solar system can explain tides, eclipses of the sun and the moon, and the motion of the planets in the sky relative to the stars. Earth’s spin axis is fixed in direction over the short term but tilted relative to its orbit around the sun. The seasons are a result of that tilt and are caused by the differential intensity of sunlight on different areas of Earth across the year.

By the end of grade 12. Kepler’s laws describe common features of the motions of orbiting objects, including their elliptical paths around the sun. Orbits may change due to the gravitational effects from, or collisions with, other objects in the solar system. Cyclical changes in the shape of Earth’s orbit around the sun, together with changes in the orientation of the planet’s axis of rotation, both occurring over tens to hundreds of thousands of years, have altered the intensity and distribution of sunlight falling on Earth. These phenomena cause cycles of ice ages and other gradual climate changes.

Earth exchanges mass and energy with the rest of the solar system. It gains or loses energy through incoming solar radiation, thermal radiation to space, and gravitational forces exerted by the sun, moon, and planets. Earth gains mass from the impacts of meteoroids and comets and loses mass from the escape of gases into space. (p.180)


AAAS Benchmarks for Science Literacy Project 2061

Benchmarks: American Association for the Advancement of Science

By the end of the 8th grade, students should know that

Because every object is moving relative to some other object, no object has a unique claim to be at rest. Therefore, the idea of absolute motion or rest is misleading. 10A/M1*
Telescopes reveal that there are many more stars in the night sky than are evident to the unaided eye, the surface of the moon has many craters and mountains, the sun has dark spots, and Jupiter and some other planets have their own moons. 10A/M2

By the end of the 12th grade, students should know that

To someone standing on the earth, it seems as if it is large and stationary and that all other objects in the sky orbit around it. That perception was the basis for theories of how the universe is organized that prevailed for over 2,000 years. 10A/H1*

Ptolemy, an Egyptian astronomer living in the second century A.D., devised a powerful mathematical model of the universe based on continuous motion in perfect circles, and in circles on circles. With the model, he was able to predict the motions of the sun, moon, and stars, and even of the irregular “wandering stars” now called planets. 10A/H2*

In the 1500s, a Polish astronomer named Copernicus suggested that all those same motions could be explained by imagining that the earth was turning around once a day and orbiting around the sun once a year. This explanation was rejected by nearly everyone because it violated common sense and required the universe to be unbelievably large. Worse, it flew in the face of the belief, universally held at the time, that the earth was at the center of the universe. 10A/H3*

Johannes Kepler, a German astronomer, worked with Tycho Brahe for a short time. After Brahe’s death, Kepler used his data to show mathematically that Copernicus’ idea of a sun-centered system worked well if uniform circular motion was replaced with uneven (but predictable) motion along off-center ellipses. 10A/H4*

Using the newly invented telescope to study the sky, Galileo made many discoveries that supported the ideas of Copernicus. It was Galileo who found the moons of Jupiter, sunspots, craters and mountains on the moon, and many more stars than were visible to the unaided eye. 10A/H5

Writing in Italian rather than in Latin (the language of scholars at the time), Galileo presented arguments for and against the two main views of the universe in a way that favored the newer view. His descriptions of how things move provided an explanation for why people might notice the motion of the earth. Galileo’s writings made educated people of the time aware of these competing views and created political, religious, and scientific controversy. 10A/H6*

Tycho Brahe, a Danish astronomer, proposed a model of the universe that was popular for a while because it was somewhat of a compromise of Ptolemy’s and Copernicus’ models. Brahe made very precise measurements of the positions of the planets and stars in an attempt to validate his model. 10A/H7**

The work of Copernicus, Galileo, Brahe, and Kepler eventually changed people’s perception of their place in the universe. 10A/H8** (SFAA)

By the end of the 12th grade, students should know that

Isaac Newton, building on earlier descriptions of motion by Galileo, Kepler, and others, created a unified view of force and motion in which motion everywhere in the universe can be explained by the same few rules. Newton’s system was based on the concepts of mass, force, and acceleration; his three laws of motion relating them; and a physical law stating that the force of gravity between any two objects in the universe depends only upon their masses and the distance between them. 10B/H1*

Newton’s mathematical analysis of gravitational force and motion showed that planetary orbits had to be the very ellipses that Kepler had proposed two generations earlier. 10B/H2*

The Newtonian system made it possible to account for such diverse phenomena as tides, the orbits of planets and moons, the motion of falling objects, and the earth’s equatorial bulge. 10B/H3*

For several centuries, Newton’s science was accepted without major changes because it explained so many different phenomena, could be used to predict many physical events (such as the appearance of Halley’s comet), was mathematically sound, and had many practical applications. 10B/H4

Although overtaken in the 1900s by Einstein’s relativity theory, Newton’s ideas persist and are widely used. Moreover, his influence has extended far beyond physics and astronomy, serving as a model for other sciences and even raising philosophical questions about free will and the organization of social systems. 10B/H5*

By the end of the 12th grade, students should know that

Prior to the 1700s, many considered the earth to be just a few thousand years old. By the 1800s, scientists were starting to realize that the earth was much older even though they could not determine its exact age. 10D/H1*

In the early 1800s, Charles Lyell argued in Principles of Geology that the earth was vastly older than most people believed. He supported his claim with a wealth of observations of the patterns of rock layers in mountains and the locations of various kinds of fossils. 10D/H2*

In formulating and presenting his theory of biological evolution, British naturalist Charles Darwin adopted Lyell’s claims about the age of the earth and his assumption that the processes that occurred in the past are the same as the processes that occur today. 10D/H3*

By the end of the 5th grade, students should know that

The patterns of stars in the sky stay the same, although they appear to move across the sky nightly, and different stars can be seen in different seasons. 4A/E1

Telescopes magnify the appearance of some distant objects in the sky, including the moon and the planets. The number of stars that can be seen through telescopes is dramatically greater than can be seen by the unaided eye. 4A/E2

Planets change their positions against the background of stars. 4A/E3

The earth is one of several planets that orbit the sun, and the moon orbits around the earth. 4A/E4

Stars are like the sun, some being smaller and some larger, but so far away that they look like points of light. 4A/E5

A large light source at a great distance looks like a small light source that is much closer. 4A/E6** (BSL)

By the end of the 8th grade, students should know that

The sun is a medium-sized star located near the edge of a disc-shaped galaxy of stars, part of which can be seen as a glowing band of light that spans the sky on a very clear night. 4A/M1a

The universe contains many billions of galaxies, and each galaxy contains many billions of stars. To the naked eye, even the closest of these galaxies is no more than a dim, fuzzy spot. 4A/M1bc

The sun is many thousands of times closer to the earth than any other star. Light from the sun takes a few minutes to reach the earth, but light from the next nearest star takes a few years to arrive. The trip to that star would take the fastest rocket thousands of years. 4A/M2abc

Some distant galaxies are so far away that their light takes several billion years to reach the earth. People on earth, therefore, see them as they were that long ago in the past. 4A/M2de

Nine planets of very different size, composition, and surface features move around the sun in nearly circular orbits. Some planets have a variety of moons and even flat rings of rock and ice particles orbiting around them. Some of these planets and moons show evidence of geologic activity. The earth is orbited by one moon, many artificial satellites, and debris. 4A/M3

Many chunks of rock orbit the sun. Those that meet the earth glow and disintegrate from friction as they plunge through the atmosphere—and sometimes impact the ground. Other chunks of rock mixed with ice have long, off-center orbits that carry them close to the sun, where the sun’s radiation (of light and particles) boils off frozen materials from their surfaces and pushes it into a long, illuminated tail. 4A/M4*

By the end of the 12th grade, students should know that

The stars differ from each other in size, temperature, and age, but they appear to be made up of the same elements found on earth and behave according to the same physical principles. 4A/H1a

Unlike the sun, most stars are in systems of two or more stars orbiting around one another. 4A/H1b

On the basis of scientific evidence, the universe is estimated to be over ten billion years old. The current theory is that its entire contents expanded explosively from a hot, dense, chaotic mass. 4A/H2ab

Stars condensed by gravity out of clouds of molecules of the lightest elements until nuclear fusion of the light elements into heavier ones began to occur. Fusion released great amounts of energy over millions of years. 4A/H2cd

Eventually, some stars exploded, producing clouds containing heavy elements from which other stars and planets orbiting them could later condense. The process of star formation and destruction continues. 4A/H2ef

Increasingly sophisticated technology is used to learn about the universe. Visual, radio, and X-ray telescopes collect information from across the entire spectrum of electromagnetic waves; computers handle data and complicated computations to interpret them; space probes send back data and materials from remote parts of the solar system; and accelerators give subatomic particles energies that simulate conditions in the stars and in the early history of the universe before stars formed. 4A/H3

Mathematical models and computer simulations are used in studying evidence from many sources in order to form a scientific account of the universe. 4A/H4

As the earth and other planets formed, the heavier elements fell to their centers. On planets close to the sun (Mercury, Venus, Earth, and Mars), the lightest elements were mostly blown or boiled away by radiation from the newly formed sun; on the outer planets (Jupiter, Saturn, Uranus, Neptune, and Pluto) the lighter elements still surround them as deep atmospheres of gas or as frozen solid layers. 4A/H5** (SFAA)

Our solar system coalesced out of a giant cloud of gas and debris left in the wake of exploding stars about five billion years ago. Everything in and on the earth, including living organisms, is made of this material. 4A/H6** (SFAA)

Soundly Proving the Curvature of the Earth at Lake Pontchartrain

Excerpted from an article by Mick West

A classic experiment to demonstrate the curvature of a body of water is to place markers (like flags) a fixed distance above the water in a straight line, and then view them along that line in a telescope. If the water surface is flat then the markers will appear also in a straight line. If the surface of the water is curved (as it is here on Earth) then the markers in the middle will appear higher than the markers at the ends.

Here’s a highly exaggerated diagram of the effect by Alfred Russel Wallace in 1870, superimposed over an actual photograph.

Lake Pontchartrain power lines demonstrating the curvature Metabunk

This is a difficult experiment to do as you need a few miles for the curvature to be apparent. You also need the markers to be quite high above the surface of the water, as temperature differences between the water and the air tend to create significant refraction effects close to the water.

However Youtuber Soundly has found a spot where there’s a very long line of markers permanently fixed at constant heights above the water line, clearly demonstrating the curve. It’s a line of power transmission towers at Lake Pontchartrain, near New Orleans, Louisiana.

The line of power lines is straight, and they are all the same size, and the same height above the water. They are also very tall, and form a straight line nearly 16 miles long. Far better than any experiment one could set up on a canal or a lake. You just need to get into a position where you can see along the line of towers, and then use a powerful zoom lense to look along the line to make any curve apparent

One can see quite clearly in the video and photos that there’s a curve. Soundly has gone to great lengths to provide multiple videos and photos of the curve from multiple perspectives. They all show the same thing: a curve.

Lake Pontchartrain curve around Earth

One objection you might make is that the towers could be curving to the right. However the same curve is apparent from both sides, so it can only be curving over the horizon.



People have asked why the curve is so apparent in one direction, but not in the other. The answer is compressed perspective. Here’s a physical example:


Compressed perspective on a car

That’s my car, the roof of which is slightly curved both front to back and left to right. I’ve put some equal sized chess pawns on it in two straight lines. If we step back a bit and zoom in we get:

Compressed perspective on a car II

Notice a very distinct curve from the white pieces, but the “horizon” seems to barely curve at all.

Similarly in the front-back direction, where there’s an even greater curve:

Compressed perspective on a car III

There’s a lot more discussion with photos here Soundly Proving the Curvature of the Earth at Lake Pontchartrain



Coding weather forcecasting

Coding weather forcecasting

GR2Analyst Tornado GRLEVELX



Unleash Your Inner Geek With These Excellent Weather Radar Programs


Sample programs

Gibson Ridge Software, LLC (GRS) was created in March 2005 and produces viewers for weather radar data. GRS applications include GRLevel2 for viewing Level II radar data and GRLevel3 for viewing Level III data. Both viewers feature high speed, high quality radar displays with an intuitive user interface. All GRS applications are written in multithreaded C++ using the base Windows APIs for speed and efficiency.


ProductsGRLevel3 2.00

GR2Analyst 2.00




View storm features in 3D with GR2Analyst’s Volume Explorer

Display 124 nm and 248 nm sweeps for a complete view of hurricanes and other large-scale phenomena

Smoothing reconstructs features distorted by standard bin-oriented displays 

See severe thunderstorm and tornado warnings along with details of Nexrad-identified threats

Learning standards

Massachusetts Earth Science

8.MS-ESS2-5. Interpret basic weather data to identify patterns in air mass interactions and the relationship of those patterns to local weather.

8.MS-ESS2-6. Describe how interactions involving the ocean affect weather and climate on a regional scale, including the influence of the ocean temperature as mediated by
energy input from the Sun and energy loss due to evaporation or redistribution via
ocean currents.

Common Core Math Skills


MP1 Make sense of problems and persevere in solving them Chapters are all based around solving real-world robot problems; students must make sense of the problems to inform their solutions

MP2 Reason abstractly and quantitatively Programming requires students to reason about physical quantities in the world to plan a solution, then calculate or estimate them for the robot

MP4 Model with mathematics Many processes, including the process of programming itself, must be systematically modeled on both explicit and implicit levels


HS-ETS1-2. Design a solution to a complex real-world problem by breaking it down into smaller, more manageable problems that can be solved through engineering.