Tag Archives: space

Today is the Autumnal Equinox – Here’s What That Means

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Today is the Autumnal Equinox, the first day of fall in the northern hemisphere. The new season officially begins at 20:02 UTC, which is 4:02 PM Eastern Daylight Time.

The astronomical seasons, as opposed to the meteorological seasons,  are a product of Earth’s axial tilt – a 23.5° angle – and the movement of the planet around the sun. During the autumn months, the Earth’s axis is tilted neither toward nor away from the sun. This position distributes the sun’s energy equally between the northern and southern hemispheres.

Since the summer solstice in June, the arc of the sun’s apparent daily passage across the sky has been moving southward and daylight hours have been decreasing. Today, the sun appears directly overhead at the equator and we have approximately equal hours of day and night. The word “equinox” is derived from Latin and means “equal night”.

With the sun sitting lower in the sky and daylight hours continuing to shorten, autumn is a season of falling temperatures. According to NOAA, the average high temperature in most US cities drops about 10°F between September and October.

Earth’s solstices and equinoxes. Image Credit: NASA

Solar Eclipse Cools NYC by Nearly 4°F

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Monday marked the first time in decades that a total solar eclipse was visible in the continental US. The path of totality was about 70 miles wide and passed through 14 states, from Oregon to South Carolina. The rest of the country, however, saw varying degrees of a partial eclipse.

Partial Solar Eclipse 2017 seen from NYC. Credit: Melissa Fleming

Here in New York City, the magnitude was only about 72%. Nonetheless, this celestial event had a noticeable impact on the local temperature. Our weather station in mid-town Manhattan showed a drop of 3.7°F as the moon briefly obscured the afternoon sun.

The next solar eclipse that will be visible from the east coast will take place on April 8, 2024. So, hold on to those eclipse viewing glasses!

The solar eclipse peaked at 2:44 PM EDT in NYC. Credit: The Weather Gamut

The Great American Solar Eclipse of 2017

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The Great American Solar Eclipse will take place on Monday, August 21. It will be the first time that a total solar eclipse has been visible anywhere in the contiguous US since 1979 and the first event of its kind to travel across the entire continent since 1918.

A solar eclipse occurs when the moon passes between the Earth and the Sun, casting a shadow on the planet’s surface. Communities that are located in the large, but lighter penumbral shadow will see a partial eclipse. Those in the smaller, but darker umbral shadow will experience a total solar eclipse. Moving across the Earth, the umbral shadow creates what is known as a path of totality.

Credit: NASA

On Monday, this path will cross through fourteen states, from Oregon to South Carolina. However, every state in the Lower 48, as well as parts of Mexico and Canada, will see some degree of a partial eclipse.

This celestial event is also expected to affect the weather across the country. As the moon briefly obscures the Sun, temperatures are forecast to drop a few degrees. This, in turn, will also cause the winds to slacken.

When viewing this historic event, do not look directly at the Sun. Doing so will cause serious eye damage. Use special eclipse viewing glasses or a method of indirect viewing, such as a pinhole projector.

Path of Totality for Solar Eclipse 2017. Credit: GreatAmericanEclipse

Aphelion 2017: Earth Farthest from Sun Today

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The Earth will reach its farthest point from the Sun today – an event known as the aphelion. It will officially take place at 20:11 UTC, which is 4:11 PM Eastern Daylight Time.

This annual event is a result of the elliptical shape of the Earth’s orbit and the slightly off-centered position of the Sun inside that path. The exact date of the Aphelion differs from year to year, but it’s usually in early July – summer in the northern hemisphere.

While the planet’s distance from the Sun is not responsible for the seasons, it does influence their length. As a function of gravity, the closer the planet is to the Sun, the faster it moves. Today, Earth is about 152 million kilometers (94 million miles) away from the Sun. That is approximately 5 million kilometers (3 million miles) further than during the perihelion in early January. That means the planet will move more slowly along its orbital path than at any other time of the year. As a result, summer is elongated by a few days in the northern hemisphere.

The word, aphelion, is Greek for “away from the sun”.

Earth is farthest from the Sun during summer in the northern hemisphere. Credit: TimeandDate.com

Earth’s Perihelion 2017

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The Earth will reach its Perihelion today at 14:18 UTC, which is 9:18 AM Eastern Standard Time. This is the point in the planet’s orbit where it comes closest to the Sun.

This annual event is due to the elliptical shape of the Earth’s orbit and the off-centered position of the Sun inside that path. The exact date of the Perihelion differs from year to year, but it’s usually in early January – winter in the northern hemisphere. The Earth will be furthest from the Sun in July.

While the planet’s distance from the Sun is not responsible for the seasons, it does influence their length. As a function of gravity, the closer the planet is to the Sun, the faster it moves. Today, the Earth is 147.1 million kilometers (91.4 million miles) away from the Sun. That is approximately 5 million kilometers (3 million miles) closer than it will be in early July. This position allows the planet to speed up by about one-kilometer/second. As a result, winter in the northern hemisphere is about five days shorter than summer.

The word, perihelion, is Greek for “near sun”.

Earth is closest to the Sun during the northern hemisphere’s winter. Credit: TimeandDate.com

GOES-R Satellite will Improve Weather Forecasts

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Satellites have helped forecasters predict the weather for more than forty years. Now, they are getting a major upgrade.

Launched from Cape Canaveral Air Force Station on Saturday night, the GOES-R is the newest model in NOAA’s Geostationary Operational Environmental Satellite series. It has been nearly a decade since the last upgrade and this one is loaded with new technology.

Carrying 34 different weather products, the main instrument is the Advanced Baseline Imager (ABI). Essentially a camera that views the western hemisphere’s weather, oceans, and environment, it offers 3 times the spectral information, 4 times the spatial resolution, and temporal coverage that is five times faster than the previous GOES model. In other words, it will provide a clearer and faster image of what is going on in the atmosphere than ever before, allowing for better forecasts. This, in turn, means improved protection for lives and property, which is the main mission of the National Oceanic and Atmospheric Administration.

Other instruments onboard include a lightning mapper, which will continuously measure the lightning activity over both North and South America. This information is important because the rate of lightning is related to a storm’s updraft. Better lightning data can increase the lead-time for warnings on storms that could produce severe weather. Another important device is the magnetometer. It will monitor space weather such as solar storms  that produce the northern lights and can, when strong enough, disrupt power grids and telecommunications.

Once in orbit, GOES-R will become known as GOES-16 (letters are only used while it is in development on the ground). After a calibration and testing period of several months, its data will become available to forecasters. If all goes well, it should be online by next year’s hurricane season.

GOES-R satellite. Credit: NOAA

GOES-R satellite. Credit: NOAA

Earth’s Aphelion 2016

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The Earth will reach its farthest point from the Sun today – an event known as the aphelion.  It will officially take place at 16:24 UTC, which is 12:24 PM Eastern Daylight Time.

This annual event is a result of the elliptical shape of the Earth’s orbit and the off-centered position of the Sun inside that path. The exact date of the Aphelion differs from year to year, but it’s usually in early July – summer in the northern hemisphere.

While the planet’s distance from the Sun is not responsible for the seasons, it does influence their length. As a function of gravity, the closer the planet is to the Sun, the faster it moves. Today, Earth is about 152 million kilometers (94 million miles) away from the Sun. That is approximately 5 million kilometers (3 million miles) further than during the perihelion in early January. That means the planet will move more slowly along its orbital path than at any other time of the year. As a result, summer is elongated by a few days in the northern hemisphere.

The word, aphelion, is Greek for “away from sun”.

Image Credit: mydarksky.org

Earth is farthest from the Sun during summer in the northern hemisphere. Image Credit: mydarksky.org

Earth’s Perihelion 2016

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The Earth will reach its Perihelion today at 22:49 UTC, which is 5:49 PM Eastern Standard Time. This is the point in the planet’s orbit where it comes closest to the Sun.

This annual event is due to the elliptical shape of the Earth’s orbit and the off-centered position of the Sun inside that path. The exact date of the Perihelion differs from year to year, but it’s usually in early January – winter in the northern hemisphere. The Earth will be furthest from the Sun in July.

While the planet’s distance from the Sun is not responsible for the seasons, it does influence their length. As a function of gravity, the closer the planet is to the Sun, the faster it moves. Today, the Earth is 147.1 million kilometers (91.4 million miles) away from the Sun. That is approximately 5 million kilometers (3 million miles) closer than it will be in early July. This position allows the planet to speed up by about one-kilometer/second. As a result, winter in the northern hemisphere is about five days shorter than summer.

The word, perihelion, is Greek for “near sun”.

Earth's Perihelion and Aphelion. Credit: Time and Date.com

Earth’s Perihelion and Aphelion. Credit: TimeandDate.com

Earth’s Aphelion 2015

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The Earth will reach its Aphelion today at 19:41 UTC, which is 3:41 PM Eastern Daylight Time. This is the point in the planet’s orbit where it is farthest from the Sun.

This annual event is a result of the elliptical shape of the Earth’s orbit and the off-centered position of the Sun inside that path. The exact date of the Aphelion differs from year to year, but it’s usually in early July – summer in the northern hemisphere.

While the planet’s distance from the Sun is not responsible for the seasons, it does influence their length. As a function of gravity, the closer the planet is to the Sun, the faster it moves. Today, Earth is about 152 million kilometers (94 million miles) away from the Sun. That is approximately 5 million kilometers (3 million miles) further than during the perihelion in early January. That means the planet will move more slowly along its orbital path than at any other time of the year. As a result, summer is elongated by a few days in the northern hemisphere.

The word, aphelion, is Greek for “away from sun”.

Image Credit: mydarksky.org

Image Credit: mydarksky.org

Earth’s Perihelion 2015

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The Earth reached its Perihelion today at 6:36 UTC, which is 1:36 AM Eastern Standard Time. This is the point in the planet’s orbit where it comes closest to the Sun.

This annual event is due to the elliptical shape of the Earth’s orbit and the off-centered position of the Sun inside that path. The exact date of the Perihelion differs from year to year, but it’s usually in early January – winter in the northern hemisphere. The Earth will be furthest from the Sun in July.

While the planet’s distance from the Sun is not responsible for the seasons, it does influence their length. As a function of gravity, the closer the planet is to the Sun, the faster it moves. Today, the Earth is about 146 million kilometers away from the Sun. That is approximately 5 million kilometers (3 million miles) closer than in early July. This position allows the planet to speed up by about one-kilometer/second. As a result, winter in the northern hemisphere is about five days shorter than summer.

The word, perihelion, is Greek for “near sun”.

Image Credit: mydarksky.org

Image Credit: mydarksky.org