Continents may club together at equator, here’s how Earth may look in future
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Simulations showing the evolution of Earth over next 200-250 million years. (Photo: Geochemistry, Geophysics and Geosystems)
The Earth has evolved over millions of years with tectonic plates changing the face of the planet from one era to another. Breaking super-continent Pangaea, these tectonic plates have arranged the Earth’s surface into seven continents and five oceans.
Scientists say these tectonic plates are not finished yet and the Earth is still evolving. They have assessed how the current structure of the planet will change over the next 200-250 million years.
Led by Michael Way of the NASA Goddard Institute for Space Studies, researchers looked at how the evolution of plate tectonics, the Sun’s increase in brightness, and a slightly slower rotation rate would lead to future climate scenarios.
They found two different scenarios that may occur in future and the difference in the mean surface temperatures of these two cases differ by several degrees Celsius.
In a study published in the journal, “Geochemistry, Geophysics, Geosystems”, the researchers said, “In one case the present-day continents form into a single landmass near the equator, and in the other case Antarctica stays put, but the rest of the present-day continents are mostly pushed well north of the equator.”
Earth halfway through current continental formation
The continents on Earth aggregate into supercontinents and then disperse on a cycle of 400-600 million years known as the supercontinent cycle.
“Pangaea formed around 310 million years ago and started breaking up around 180 million years ago. The next supercontinent will most likely form in 200-250 million years, meaning the Earth is currently about halfway through the scattered phase of the current supercontinent cycle,” the paper said.
The researchers established strong links between large-scale tectonics (movement of the Earth’s lithospheric plates) and climate changes.
Individual grid cell for a 50-years climatological mean (from the last 50 years of each run) of the months of December, January and February (top) and June, July and August (bottom). (Photo: Geochemistry, Geophysics, Geosystems)
They said it would be interesting to know what the Earth’s climate could be like in a distant future when continental movements would have taken the planet away from the current continental configuration.
Researchers explored two plausible formations. First would be Aurica, a low latitude supercontinent developing over next 250 million years.
The second would be Amasia, a high latitude northern supercontinent plus a smaller Antarctic subcontinent taking shape in about 200 million years from now.
“Amasia is essentially an Arctic supercontinent with an independent and isolated Antarctic continent, meaning both poles are covered by land, and much of that is covered by ice,” the paper said.
Major changes expected in future
Several models have been designed to predict the Earth’s near-future climate. While one set of researchers have explored the Earth’s deep-time future climate by looking at increases in carbon-dioxide and solar insolation through time, some others have investigated climate effects induced by additional changes in the topography of the planet.
Researchers found that high altitude land on Amasia would lead to creation of ice sheets and the white supercontinent would reflect back more of the Sun’s heat.
The continents on Earth aggregate into supercontinents and then disperse on a cycle of 400600 million years.
The lack of a northern polar ocean means that more ice resides on land and in lakes throughout the year near the North Pole, as we see in present-day Antarctica.
Meanwhile, Aurica will have little snow or ice and an average temperature of around 20 degrees Celsius.
“The geological formations on the ever-changing surface of the Earth have a strong influence on our climate,” the researchers said citing how the Himalayas, a consequence of the India-Eurasia collision, help monsoon climatic conditions.
Studying these climatic changes based on topographic movements will also help astronomers create a climate model of an Earth-like exoplanet using the parameters known to sustain habitability and a stable biosphere.
“Using the deep-time future Earth as a basis for exoplanetary climate studies allows us to establish sensitivity ranges for the habitability and climate stability of the future Earth and its distant cousins in our galaxy,” the paper said.
Here’s the difference between meteorological, astronomical seasons
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Orlando, FLA. – It is time to turn your calendar to September, which also happens to be the official start of meteorological fall!
Some might say, fall doesn’t begin for a few weeks but for meteorologists, fall has officially arrived.
What is the difference between meteorological and astronomical seasons?
Climatologists and meteorologists break down the four seasons into groups of three months based on the annual temperatures. The coldest months of December, January and February make up meteorological winter, whereas the hottest months of June, July and August make up the hottest months during meteorological summer. Each season starts the first of the month and ends at the end of the third month. For example, summer begins June 1 and ends Aug. 31.
Astronomical seasons, which most people are used to hearing about, are based on the sun’s position in the sky. This means summer and winter season begins when the sun passes the farthest point north of the equator or at its solstice. And spring and fall begin when the sun is exactly above the equator, meaning equal hours of daytime and nighttime.
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Why do meteorologists use different dates?
According to the National Oceanic Atmospheric Administration, weather observations and forecasting led to the creation of these seasons, which are closely tied to our monthly civil calendar compared to astronomical seasons. Having a more consistent length of seasons makes it much easier to calculate season statistics that are very useful for those who depend on weather forecasts, like agriculture and commerce.
How much do the start dates differ?
Seasonal start dates can fluctuate between the 20-22 every three months and include time of day, where meteorological season starts remain consistently the first of every third month. Below is an example of 2021 seasons.
Stargazing in September: The autumn equinox is upon us
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This month sees a turning point in both the heavens and the Earth below. On 22 September, the Sun slips south of the Earth’s equator. The northern hemisphere tips from the summer half of the year to winter: long leisurely daylight hours of sunbathing give way to protracted cold nights huddled in front of the fire.
Astronomers are among those who celebrate the change of seasons, as there’s more time to observe the wonders of the night sky. And they’ve given this handover date a name: the autumn equinox. The corresponding date in March, when the Sun moves back north of the equator is the spring equinox – or vernal equinox, from the Latin for “spring”. The word equinox itself is Latin, meaning “equal night”, because – on this halfway date between midsummer and midwinter – the day and night are both exactly 12 hours long.
Or are they?
Let’s look at actual sunrise and sunset times. That depends a lot on where you live, so I’ve selected the village of Dunsop Bridge in Lancashire, which the Ordnance Survey says is the centre of Great Britain. On 22 September, sunrise occurs at 6.55 am, and sunset at 7.08 pm. Do a quick sum, and you’ll discover the day length is 12 hours and 13 minutes, and the night is 11 hours 47 minutes long. So much for equal day and night!
The size of the Sun’s beaming face is one reason for this discrepancy. What astronomers define as the Sun’s position is the location of its centre. When the Sun’s midpoint rises, half of its face is already above the horizon, and for most of us that means sunrise has already happened.
Our atmosphere comes into the fray, too, acting like a giant lens. As the Sun’s rays whizz through the air, they are bent by refraction, so the Sun appears higher in the sky than it otherwise would. The effect is surprisingly large, raising the Sun by more than its own diameter. Think of the newly-risen Sun sitting on the horizon; if you could strip away the Earth’s atmosphere you wouldn’t see it at all, because the Sun is actually still below the horizon.
Both these effects mean we get more than 12 hours of sunshine on the day of the equinox. However, there is a day when daytime and night-time are equal, sometimes called the “equilux” (meaning “equal light”). It occurs a few days after the equinox, and this year for Dunsop Bridge it’s 25 September.
You can find sunrise and sunset times for your own location from a number of websites, such as www.timeanddate.com/sun. But be prepared for the Sun to flaunt the predictions yet again, unless you have an absolutely flat horizon. If you’re surrounded by hills, mountains, trees or buildings the Sun will take extra time to clear them in the morning, and disappear behind them earlier than predicted in the evening.
What’s up
Like a lantern hanging in the gloaming, the Evening Star shines in the south-west after sunset. In reality, this ‘star’ is our neighbour planet Venus. There’s a lovely sight on 9 and 10 September when Venus is joined by the crescent Moon. To the lower right of Venus, and best seen in binoculars, you may spot the innermost of the planets, tiny Mercury.
After the sky grows dark, the night is dominated by brilliant Jupiter, the colossus of the Solar System, and its fainter sidekick Saturn. The Moon pairs up with Saturn on 16 September, and passes near Jupiter on 17 and 18 September.
The night sky at around 11 pm this month (Nigel Henbest)
The two giant planets are currently in a region of faint stars, outlining dim constellations that it takes a bit of time to get acquainted with. Jupiter and Saturn lie either side of the ancient constellation Capricornus. It takes a bit of imagination to see this distorted triangle as the traditional figure of a Sea-Goat – a mythical creature with a goat’s head and a fish’s tail.
The stars to the upper left of Jupiter form the torso of Aquarius, the Water-Carrier. He’s pouring a stream of liquid that appears as a cascade of stars passing Jupiter to drop down to the star Fomalhaut, marking the mouth of the Southern Fish (Piscis Austrinus).
Turning round to face the opposite direction, you’ll see the familiar seven stars of the Plough low in the north, between bright orange Arcturus to the left and yellow Capella on the right. Higher up, look out for the distinctive W-shape of stars depicting Queen Cassiopeia.
Diary
5 September: Venus near Spica
7 September, 1.51 am: New Moon
9 September: Crescent Moon near Venus
10 September: Crescent Moon near Venus
12 September: Moon near Antares
13 September, 9.39 pm: First Quarter Moon
14 September: Neptune at opposition; Mercury at greatest elongation east
16 September: Moon near Saturn
17 September: Moon near Jupiter
18 September: Moon near Jupiter
21 September, 0.54am: Full Moon
22 September, 8.21pm: Autumn Equinox
25 September: Moon near the Pleiades
26 September: Moon near Aldebaran
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29 September, 2.57am: Last Quarter Moon
Philip’s Stargazing 2022 (Philip’s £6.99) by Nigel Henbest is your guide to everything that’s going on in the sky next year