Thursday, October 22


They struck the Earth's ionosphereand their numbers diminished. The ionosphere of Eisberg was much deeper and, although the intensity was less, the duration was much longer. Extensive reports on the condition of the ionosphere poured into headquarters. Without the landing grid and the power it took from the ionospherethey could not receive supplies from the rest of the universe.

Then we were able to modify that to heave sand and to let it tap the ionosphere. A region of the atmosphere that begins at an altitude of about thirty miles. An everyday activity is one you do every day. Thanks, English. Practice using "everyday," one word, and "every day," two words, in this fun quiz with … everyday example sentences! Words nearby ionosphere iononeionopauseionophoreionophoresisionosondeionosphereionospheric waveionotropic receptorionotropyiontophoresisioof.

Example sentences from the Web for ionosphere They struck the Earth's ionosphereand their numbers diminished. Unwise Child Gordon Randall Garrett. Sand Doom William Fitzgerald Jenkins. A region of the Earth's upper atmosphere, extending from a height of 70 km 43 mi to km mi and containing atoms that have been ionized by radiation from the Sun.

Ionosphere and magnetosphere

The ionosphere lies mostly in the lower thermosphere and is subdivided into three regions, the D region 70 km to 90 km; 43 to 56 mithe E region 90 km to km; 56 to 93 miand the F region km to km; 93 to mi. The concentration of ionized atoms is lowest in the D region, intermediate in the E region, and highest in the F region. The ionosphere is useful for radio transmission because radio waves, which normally propagate in straight lines, are reflected off the ionized gas particles, thereby being transmitted long distances across the Earth's curved surface.

See more at D region E region F region. All rights reserved.Specific ionization conditions vary greatly between day left and night rightcausing radio waves to reflect off different layers of the ionosphere or transmit through them, depending upon their frequency and their angle of transmission. At night, with no intervening layers of the ionosphere present, reflection off the F layer can yield extremely long transmission ranges.

Discovery of the ionosphere extended over nearly a century. The notion of…. Chief among these timescales is the year solar cycle, defined by the waxing and waning of solar activity as seen in the number of sunspots. Within the solar cycle, solar storms such as flares and coronal mass…. Space weather can change the density structure of the ionosphere by creating areas of enhanced density.

This modification of the ionosphere makes GPS less accurate and…. These ions result from the removal of electrons from atmospheric gases by solar ultraviolet radiation. Extending from about 80 to km about 50 to miles in altitude, the ionosphere is an electrically conducting region capable of reflecting radio signals back to Earth. Spectacular visible auroras are generated in this region, particularly along approximately circular zones around the poles, by the interaction of nitrogen and oxygen atoms in the atmosphere with episodic bursts of energetic particles originating from the Sun.

In the ionosphere, ionization is accomplished not through heating of the plasma but rather by the flux of energetic photons from the Sun. Some of the energy also goes…. At altitudes below about 2, kilometres, the plasma is referred to as the ionosphere. Thousands of rocket probes have helped chart the vertical structure of this region of the atmosphere, and numerous satellites have provided latitudinal and longitudinal information.

The ionosphere…. Beginning at about 50 kilometres and extending above 1, kilometres with a maximum at kilometres, the ionosphere is formed primarily by the action of sunlight on atmospheric particles. There sunlight strips electrons from neutral atoms and produces a partially ionized gas plasma. Because of…. This permits target detection at distances from about to 2, nautical miles to 3, km.

Various constituents in the top of the atmosphere are lost to space, which affects the isotopic composition of the remaining gases.

For example, because hydrogen is lost preferentially…. In the suggestion was proved to be accurate when pulses of radio energy were transmitted vertically upward and returning pulses were received back….

Ionization is caused primarily by radiation from the Sun, so that the layers vary in height and in reflectivity…. As its name implies, the ionosphere is composed of ions, or charged particles, produced both by absorption of ultraviolet solar radiation and by the impact of the solar wind—the flow of charged particles streaming outward from the Sun—on the upper atmosphere. The primary ions…. Other ionospheric layers reflect radio waves sporadically, depending upon temperature and time of day.

In the need for data on a worldwide scale led him to propose…. The main instrument is the Ionospheric Research Instrument IRIan array of radio antennas spread over an area of 0. In he became a telegrapher, but increasing deafness forced him to retire in He then devoted himself to investigations of electricity.The ionosphere is defined as the layer of the Earth's atmosphere that is ionized by solar and cosmic radiation.

It lies km miles above the Earth. The ionized electrons behave as free particles. The Sun's upper atmosphere, the coronais very hot and produces a constant stream of plasma and UV and X-rays that flow out from the Sun and affect, or ionize, the Earth's ionosphere. During the night, without interference from the Sun, cosmic rays ionize the ionosphere, though not nearly as strongly as the Sun. These high energy rays originate from sources throughout our own galaxy and the universe -- rotating neutron starssupernovaeradio galaxiesquasars and black holes.

Thus the ionosphere is much less charged at nighttime, which is why a lot of ionospheric effects are easier to spot at night — it takes a smaller change to notice them. The ionosphere has major importance to us because, among other functions, it influences radio propagation to distant places on the Earth, and between satellites and Earth.

Image courtesy Morris Cohen, Stanford University. The ionosphere is composed of three main parts, named for obscure historical reasons: the D, E, and F regions. The electron density is highest in the upper, or F region. The F region exists during both daytime and nighttime.

During the day it is ionized by solar radiation, during the night by cosmic rays. The D region disappears during the night compared to the daytime, and the E region becomes weakened. Back to top. During the night image below, right sidethe ionosphere has only the F and E layers.

A VLF wave from a transmitter reflects off the ions in the E layer and bounces back. The D layer is normally not dense enough to reflect the radio waves. However, the E layer is, so the VLF signals go through the D layer, bounce off the E layer, and go back down through the D layer to the ground.

The signals lose energy as they penetrate through the D layer and hence radios pick up weaker signals from the transmitter during the day. When a solar flare occurs, even the D layer becomes ionized, hence allowing signals to bounce off it. Sunrise and Sunset Effects.

The reflection height for VLF waves changes from about 70 km in the daytime to about 85 km at night miles. During sunrise, sunlight strikes the ionosphere before the ground, and at sunset the light continues to strike the ionosphere after the Sun has set above the ground.

The amount of time it takes for the Sun to ionize the ionosphere once it strikes it is virtually instantaneous. So at sunrise and sunset, the signal your SID monitor picks up is basically the effect of the VLF waves bouncing off the ionosphere along the entire path from transmitter to receiver, which could be several thousand miles.

That is, the monitor picks up this process of change in conditions as sunlight sweeps over the path between transmitter and receiver. Latitude contributes too, since the equatorial daytime is the same length, but the higher latitude daytimes are highly seasonal in length.

What Is the Ionosphere? (And Who Is Steve?)

Solar Flare. Photo courtesy NASA. Thus D now becomes strong enough to reflect the radio waves at a lower altitude. So during a solar flare, the waves travel less distance bouncing off D instead of E or F.A dense layer of molecules and electrically charged particles, called the ionosphere, hangs in the Earth's upper atmosphere starting at about 35 miles 60 kilometers above the planet's surface and stretching out beyond miles 1, km. Solar radiation coming from above buffets particles suspended in the atmospheric layer.

Radio signals from below bounce off the ionosphere back to instruments on the ground. Where the ionosphere overlaps with magnetic fields, the sky erupts in brilliant light displays that are incredible to behold.

Several distinct layers make up Earth's atmosphereincluding the mesosphere, which starts 31 miles 50 km up, and the thermosphere, which starts at 53 miles 85 km up. Extreme ultraviolet radiation and X-rays from the sun bombard these upper regions of the atmosphere, striking the atoms and molecules held within those layers.

The powerful radiation dislodges negatively charged electrons from the particles, altering those particles' electrical charge. The resulting cloud of free electrons and charged particles, called ions, led to the name "ionosphere.

The concentration of ions in the ionosphere varies with the amount of solar radiation bearing down on the Earth. The ionosphere grows dense with charged particles during the day, but that density subsides at night as charged particles recombine with displaced electrons. Entire layers of the ionosphere appear and disappear during this daily cycle, according to NASA.

Solar radiation also fluctuates over an year period, meaning the sun may put out more or less radiation depending on the year. Explosive solar flares and gusts of solar wind stir up sudden changes in the ionosphere, teaming up with high-altitude winds and severe weather systems brewing on the Earth below.

The scorching-hot surface of the sun expels streams of highly charged particles, and these streams are known as solar wind. Upon reaching the Earth's magnetic field and the ionosphere below, solar winds set off a colorful chemical reaction in the night sky called an aurora. When solar winds whip across Earth, the planet stays shielded behind its magnetic field, also known as the magnetosphere. Generated by churning molten iron in the Earth's core, the magnetosphere sends solar radiation racing toward either pole.

There, the charged particles collide with chemicals swirling in the ionosphere, generating the spellbinding auroras. Scientists have found that the sun's own magnetic field squishes the Earth's weaker one, shifting auroras toward the night side of the planet, as reported by Popular Mechanics.

Near the Arctic and Antarctic circles, auroras streak across the sky every night, according to National Geographic. The colorful curtains of light, known as the aurora borealis and aurora australis, respectively, hang about miles 1, km above the Earth's surface. The auroras glow green-yellow when ions strike oxygen particles in the lower ionosphere. Reddish light often blooms along the auroras' edges, and purples and blues also appear in the nighttime sky, though this happens rarely.

Beyond auroras, the ionosphere also plays host to other impressive light shows. Incitizen scientists spotted a particularly eye-catching phenomena, which scientists struggled to explain, Live Science sister-site Space.


Bright rivers of white and pinkish light flowed over Canada, which is farther south than most auroras appear. Occasionally, dashes of green joined the mix. According to a study in the journal Geophysical Research Lettersthe green streaks within STEVE may develop similarly to how traditional auroras form, as charged particles rain down upon the atmosphere. In STEVE, however, the river of light seems to glow when particles within the ionosphere collide and generate heat among themselves.

Though reactions in the ionosphere paint the sky with brilliant hues, they can also disrupt radio signalsinterfere with navigational systems and sometimes cause widespread power blackouts. The ionosphere reflects radio transmissions below 10 megahertz, allowing the military, airlines and scientists to link radar and communication systems over long distances.

These systems work best when the ionosphere is smooth, like a mirror, but they can be disrupted by irregularities in the plasma. GPS transmissions pass through the ionosphere and therefore bear the same vulnerabilities.

One such solar storm caused the famous Quebec blackout of To save this word, you'll need to log in. Send us feedback. Watson-Wattapparently first in an unpublished letter November 8, to the secretary of the Radio Research Board, a government agency see Nature, vol.

See more words from the same year Dictionary Entries near ionosphere ionophore ionophoresis ionosonde ionosphere ionotropy Ionoxalis ion propulsion. Accessed 12 Apr. Keep scrolling for more More Definitions for ionosphere ionosphere.

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Lec 41: Ionospheric Layers and Photochemistry

Examples of ionosphere in a Sentence Recent Examples on the Web Coupled with an ionosphere that can create organic snow and the potential for an interior ocean, Triton is an exciting exploration target to understand how habitable worlds may develop in our solar system and others. First Known Use of ionospherein the meaning defined above. Learn More about ionosphere.

Time Traveler for ionosphere The first known use of ionosphere was in See more words from the same year.


Dictionary Entries near ionosphere ionophore ionophoresis ionosonde ionosphere ionotropy Ionoxalis ion propulsion See More Nearby Entries. More Definitions for ionosphere. Kids Definition of ionosphere.The ionosphere is the part of the atmosphere that is ionized by solar radiation. It plays an important part in atmospheric electricity and forms the inner edge of the magnetosphere.

It has practical importance because, among other functions, it influences radio propagation to distant places on the Earth. The lowest part of the Earth's atmosphere is called the troposphere and it extends from the surface up to about 10 km 6 miles. At heights of above 80 km 50 milesin the thermosphere, the atmosphere is so thin that free electrons can exist for short periods of time before they are captured by a nearby positive ion. This portion of the atmosphere is ionized and contains a plasma which is referred to as the ionosphere.

In a plasma, the negative free electrons and the positive ions are attracted to each other by the electromagnetic force, but they are too energetic to stay fixed together in an electrically neutral molecule.

Reference Terms. The atmosphere above 10 km is called the stratosphere, followed by the mesosphere. It is in the stratosphere that incoming solar radiation creates the ozone layer.

The number of these free electrons is sufficient to affect radio propagation. The ionosphere has irregular patches of ionization. Related Stories. Named 'dunes' by the hobbyists, the phenomenon is believed to be caused by waves of oxygen Some have observed that for a device on Earth facing space, the chilling outflow of energy from the device can be Their research suggests that devices for An international group of scientists has recently managed to do Now researchers report that those rising temperatures have led to Recently, scientists found that anthropogenic influences affected The finding A new study finds that one type of fungi can cut the The study has raised serious doubts of the likely impact of human-led interventions involving methods of cloud 'brightening' to But new research shows the starfish that devastates reef habitats can remain in its juvenile Shoots and Roots Communicate to Prevent Forage Species in the Gulf of Mexico and Most Popular Stories.

Living Well. View all the latest top news in the environmental sciences, or browse the topics below:.Other phenomena such as energetic charged particles and cosmic rays also have an ionizing effect and can contribute to the ionosphere.

The atmospheric atoms and molecules are impacted by the high energy the EUV and X-ray photons from the sun. The amount of energy photon flux at EUV and x-ray wavelengths varies by nearly a factor of ten over the 11 year solar cycle. The density of the ionosphere changes accordingly. Due to spectral variability of the solar radiation and the density of various constituents in the atmosphere, there are layers are created within the ionosphere, called the D, E, and F-layers.

Other solar phenomena, such as flares, and changes in the solar wind and geomagnetic storms also effect the charging of the ionosphere. Since the largest amount of ionization is caused by solar irradiance, the night-side of the earth, and the pole pointed away from the sun depending on the season have much less ionization than the day-side of the earth, and the pole pointing towards the sun.

Skip to main content. R1 Minor Radio Blackout Impacts. HF Radio: Weak or minor degradation of HF radio communication on sunlit side, occasional loss of radio contact.


Navigation: Low-frequency navigation signals degraded for brief intervals. Earth Sun Relationship:. Electric Power Transmission.



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