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The Winter 2010 issue of The Earth Scientist includes a variety of educational resources, ranging from astronomy to glaciers. Check out the other publications and classroom materials in our online store.

Quickie Questions - Sun - Effects of the Sun

Date Answered Questioner (age, location) Question Answer
March 10, 2010sriya (tx/usa)How can the sun be harmfulLong exposure to the Sun damages the human skin. Looking directly to the Sun will damage your eyes, to the point to completely loose your vision. There are also negative effects on technology, like damage to satellites solar pannels during Sun active periods.
December 17, 2009Robert (Australia)Considering that the sun is halway through its life, how long will it take before the average temparature on earth reaches 60 - 70 degrees and Mercury and venus explode ?
My theory is that it may be possible that mars becomes habitable if there is a change in gravity and atmosphere as the sun expands and gets closer to mars. Is this plausible ?
A star with a mass similar to our Sun and in the last phase of its life is a red giant. At this point, the Sun will have expanded to cover all the interior planets, including the Earth. But before that, in about 1.1 Gyr (1 100 000 000 years) from today) the Sun will be 10% brighter and this extra solar energy will cause the Earth's atmosphere to dry out.
January 21, 2008Richard (California)Has the Diameter of our Sun increased over the past 300 years? If yes by how much? What is the % of gain in the Suns radiation on the earths surface over the past 300 years?
I believe some part of the global warming problem is due to the increase size of our sun which brings earth a little closer to the Suns surface, increasing the affect of the increased radiation on the earths surface. Therefor not all of the global warming problem is MANS FAULT! AM I wrong?
Although there are no direct measurements of the longer-term variation and interpretations of proxy measures of variations differ; recent results suggest that the amount of solar radiation received at the outer surface of Earth's atmosphere has suffered about 0.1% variation over the last 2000 years. A 2006 study and review of existing literature, published in Nature, determined that changes in solar output within the past 400 years are unlikely to have played a major part in global warming.
April 13, 2007uma (India)what is the use to study coronal mass ejection and flares emit in sunCME's can seriously disrupt the Earth's environment. Intense radiation from the Sun, which arrives only 8 minutes after being released, can alter the Earth's outer atmosphere, disrupting long-distance radio communications. Very energetic particles pushed along by the shock wave of the CME can endanger astronauts or fry satellite electronics. These energetic particles arrive at the Earth (or Moon) about an hour later. The actual coronal mass ejection arrives at the Earth one to four days after the initial eruption, resulting in strong geomagnetic storms, aurorae and electrical power blackouts. More information in our web page Coronal Mass Ejections.
February 13, 2007bob (mississippi,united states)will the sun some day swallow earthIn about 5 billion years, the hydrogen in the center of the Sun will start to run out, the helium will get squeezed, and this will speed up the hydrogen burning. Our star will slowly puff into a red giant and will eventually eat all of the inner planets, even the Earth.
February 13, 2007andrew (Texas)Can the sun threaten the universeWell, the Sun, and the rest of the Solar System, is just an extremely small part of our galaxy the Milky Way. Not big enough to have an effect on the whole universe. But it is different for our Solar System. In about 5 billion years, the hydrogen in the center of the Sun will start to run out, the helium will get squeezed, and this will speed up the hydrogen burning. Our star will slowly puff into a red giant and will eventually eat all of the inner planets, even the Earth.
November 27, 2006Ashley (UK)The sun is a star among millions, but why is it the only one which lights up the earth?The Sun, at an average distance of 149 000 000 km (92.8 000 000 miles) to the Earth, is the closest star to our planet. The next closest star is Proxima Centauri, at 4.2 light years (39 700 000 000 000 kilometers or 24 700 000 000 000 miles) of distance, is too far away!
March 12, 2003Mary (New Mexico, USA)What are sunrays?The Sun's rays (or rays of sunlight) are radiation that comes from the Sun. This radiation is important for life on Earth because it keeps our planet warm. However, too much exposure to the Sun's rays can be harmful to your skin so remember to wear sunblock or keep your skin covered whenever you are catching some rays!
November 19, 2002David (New Jersey, USA)What is the name of the longest day of the year anywhere on earth?The longest day of the year is the summer solstice.

June 27, 2002Bob (New York, USA)At what time will the sunset on July 20, 2002 in Zip code 12764?The Weather Underground site is a great place to find sunset and sunrise information. It looks like the sun will set at 8:32 p.m. on July 20, 2002 in zip code 12764.
June 5, 2002Chris (Africa)Name the day that celebrates the Sun, space around the Earth [geospace] and how these things affect life on our planet.Sun-Earth Day! It looks like the next Sun-Earth Day is scheduled for March 18, 2003.
August 8, 2001Margery (Maryland, USA)Do sunspots affect the Earth?Sunspots don't directly affect the Earth, but they are directly related to the Solar activity cycle, which definitely does affect the Earth. One example in which this happens is through another type of Solar activity called Coronal Mass Ejections. These bursts of particles from the sun can disrupt radio communications on Earth, endanger astronauts, fry electronics, and even cause electrical blackouts.
July 23, 2001ThomWhen is the next summer solstice in 2002?The exact time and date for the summer solstice in 2002 is June 21st at 1:24 UT.
July 16, 2001Lauren (10, United Kingdom)What is the easiest way to explain why we have night and day?We have night and day because the Earth is rotating and the Sun only shines on the side that is facing toward it. It might be simpler to think of a person standing a short distance from a lit lamp. If that person spins in place, one side of them is lit up, while the other side (the side away from the lamp) is dark. In this case, the side of the person toward the lamp will be in "daylight", and the side away from the lamp will be in "night".
June 20, 2001John (16, Maine, USA)Where does the sun rise first in the US (which mountain or city sees it first)? (In Maine? Mars Hill? Mount Katahdin?)I believe Cadillac Mountain in Maine holds that claim to fame! Cadillac Mountain is in Acadia National Park and is the highest peak on the Atlantic coast. People gather there each day to be the first to see the Sun rise over the United States.
June 20, 2001Drew (6, Virginia, USA)When is the longest day (most daylight) this year 2001?June 21 is the longest day this year for those in the northern hemisphere. The Navy provides a great page that tells the exact dates of solstices and equinoxes.
April 24, 2001Tony (11, Florida, USA)How is Earth like a magnet?The conditions in the interior of the Earth actually create a magnetic field. So, it's like the Earth has a bar magnet inside of it, creating a magnetic field. The magnetic field of the Earth is surrounded by the magnetosphere.
February 5, 2001Melissa (South Carolina, USA)Does our wind come from solar wind?Though the solar wind does drive some processes that affect life on Earth, it is not responsible for the wind. Most simply, winds on Earth are due to differences in pressure within the atmosphere.
July 12, 2000Anna (Michigan, USA )Do x-rays come from the sun?Yup, x-rays come from the Sun all the time. X-rays from the Sun are emitted mainly from the corona layer of the Sun. When there is a solar flare, there could be a bigger amount of x-rays coming towards the Earth. And it only takes x-rays about 8 minutes to reach Earth!
June 30, 2000Ray (Canada )Does the sun have a shadow?

In order for the Sun to even have a shadow, there would have to be a larger source of light nearby. Since there isn't a larger star close enough that the light from it would actually surround the Sun, then no, the Sun doesn't have a shadow.

June 30, 2000Ryan (Texas, USA )How much does sunlight weigh (on Earth)?

Sunlight does not have mass, therefore it doesn't weigh anything, on Earth or anywhere else in the Universe!

June 27, 2000Marque (Texas, USA )Does the sun lose heat or does it decrease in any way per year?

The size and temperature of the Sun change very, very little over time, to the point that they are considered constant.

June 16, 2000Ryan (Texas, USA )What does a magnetosphere do?A magnetosphere protects a planet from potentially harmful particles coming from the Sun.
May 10, 2000Robert (Utah, USA)If you traveled the speed fo light toward the sun would it speed you up by the gravity's pull?

This is a rather interesting question! It seems that the answer would be no. If you are going the speed of light, you are then travelling at the fastest speed possible.

The force of gravity from the Sun could not pull hard enough to make you reach a speed even close to that. You wouldn't even know the Sun was pulling on you.

Here's a great example. Let's say you have a toy car and you want it to go down a ramp you made. Tie a string to the car and pull it down. Soon, the car will be traveling faster than you can pull, and the string will go limp. You're pulling isn't making a difference anymore!

August 31, 1999Danny (Virginia)What causes the Sun to appear red during sunsets?

The Sun looks red during a sunset because of Earth's atmosphere. When the Sun goes down, we see it through gases and dust that are in the sky.

The color it appears to be depends on what is in the air. If you see red, it is because all the other colors are being absorbed by the particles, but the color red is being reflected.

July 27, 1999Chelsi (California)What is the difference between a solar eclipse, and a lunar eclipse?A solar eclipse occurs when the Moon comes between the Earth and the Sun, so the light from the Sun is blocked. A lunar eclipse happens when the Earth comes between the Moon and the Sun, so that when we look at the Moon we see the shadow of the Earth on the Moon.
July 8, 1999Ashley (Canada)How many Earths could fit in the Sun?Over 1.3 million Earths could fit inside of the Sun. The Sun actually contains about 99% of the mass in the solar system, so it makes sense. It still blows me away every time I think about it though.
June 15, 1999Gary (North Carolina)What causes the time of sunrise at a given point to change?Day length is related to the tilt of the Earth's axis (23.5 degrees) and where on the Earth's surface you are. For you in North Carolina days are longer when the northern hemisphere is tilted toward the sun because sunlight is more direct. The more extreme north or south on Earth, the more exaggerated the day lengths. In fact, the North pole has sunrise on March 20th, and it doesn't set again for six months on September 22nd. If it weren't for the tilt of the Earth's axis every latitude on Earth would have exactly 12 hours of daylight and 12 of night each day of the year.
Check out the picture on our new SPARC page for when sunrise and sunset occur.
June 3, 1999Justin (New York, USA)I wanted to know, why when I measure the length of a shadow the same time every day, why doesn't the length of the shadow change the same amount every day?If you measure the length of an object's shadow every day at the same time and same place...it should change by getting longer as you approach winter! This is due to the motion of the Earth around the Sun.
June 1, 1999Sunday (Michigan, USA)How is it that the sun can give people energy?The sun can give people energy in a couple ways. When sunshine warms your body it is giving you some heat energy through radiation. The most important way the sun gives us energy is through the food we eat. Plants can convert the suns energy into food for itself, which we can eat. In fact, all the food we eat relies somehow on the sun. Kinda makes me hungry.
May 25, 1999Yan (Texas, USA)In our sun, the nuclei of hydrogen atoms combine to form helium atoms. Where do the electrons go?The electrons are thrown out into space. They become part of the solar wind.
May 25, 1999David (Tennessee, USA)Does the shadow cast by the moon during a solar eclipse stay in one place on the earth? If it does move, what would the different positions look like if you charted them every 30 minutes?During a total solar eclipse, a large shadow is cast onto the Earth. Even though a solar eclipse can only last a little more than 5 minutes for one location, the shadow does move across the Earth. During an annular eclipse, the Moon is farther away, so it doesn't cover the Sun completely. During this type of eclipse, there is no shadow.
May 24, 1999Nancy (Michigan, USA)My friends and I watched a ring around the sun on Saturday, May 22 for several hours. Looked much like a rainbow, but very odd. Is this an unusual occurrence?Actually, this isn't as unusual as it would appear to be. The halo you saw was caused by the refraction of light. Ice crystals in clouds refract the light, usually producing a halo at 22.5 degrees around the sun. The crystals have to be around 20 microns in size, and should be falling through the atmosphere. A similar halo occurs around the moon.
May 24, 1999Devin (New York, USA)When will the next solar eclipse occur?The next solar eclipse will occur on August 11, 1999. It will be total in Europe, the Middle East and India. It will last 2 minutes and 22 seconds.
March 3, 1999Brandy (Pennsylvania, USA)What links can I go to to receive info on solar energy?Try looking at our Solar News and Discovery page for more information about the Sun. It includes my favorite source for solar energy information.
January 5, 1999Alejandra Why do coronal mass ejections occur? What causes the Sun to eject a CME? In other words, how does it all start?Coronal mass ejections are driven by the energy released from the Sun's magnetic field. You see, it is believed that the Sun's magnetic field gets twisted or bunched up. When it gets too twisted, sometimes it forces itself free. This releases energy that ejects material off of the Sun. This event is called a coronal mass ejection or a CME.
November 9, 1998Valen (Pennsylvania, USA)How many Sun Spots are there?The number of sunspots varies from year to year. You'll find that near a solar maximum, the number for that year will be over 100. During a solar minimum, you'll find under 15! In 1989, the last solar maximum, there were 158 sunspots.
October 13, 1998Lex (Pennsylvania, USA)What is the closest you could get to the sun without it being deadly?Actually, the only thing which protects us from being killed by the Sun right now is our atmosphere. The Sun's rays are very powerful, and if the atmosphere did not exist, we would very quickly get a sunburn so bad it would kill us!
August 28, 1998Robert (Michigan, USA)I know that the Northern Lights are just gases in the atmosphere, but what makes them glow?When energetic particles from the Sun reach the Earth's upper atmosphere, they can cause the gases to glow. Here are the details.
June 22, 1998Genevieve (New Jersey, USA)I've heard that in the future, the Sun will turn into a red giant and swallow the first three planets (Earth being one of them). I know this will happen in about 5 or 6 billion years but is there any chance of life on earth moving to another location? What do you suppose will happen?If humans are still around then, I think it would be completely reasonable to think that they could move to a different location. Some of the outer moons of Jupiter and Saturn would be a lot warmer then. They might even have liquid oceans at that point.
My guess is that Earthlings will have figured out faster forms of travel by then so they could go to a completely different solar system...knowing how much has been accomplished in just 100 years on Earth, things beyond our imagination will be done in 5 billion years!
May 8, 1998Abhinav (India) On which side of the Sun are the sun spots?Well, sunspots are found on all sides of the Sun. They move with the Sun as the Sun rotates. Very often, sunspots are found near the middle of the Sun (around the equator). Don't look directly at the Sun to see this though - it can hurt your eyes!
May 4, 1998Nicolas (Ontario, Canada) What would happen if Earth moved closer to the Sun?If the Earth moved closer to the sun, the atmosphere would disappear, the oceans would boil and evaporate, and every living thing on Earth would die!
March 31, 1998Lauren (Virginia, USA) Can you give a description of the surface of the Sun?The photosphere looks somewhat boring at first glance: a disk with some dark spots. However, these sunspots are the site of strong magnetic fields. Also, if yo u look closely, you can see granulation on the surface of the Sun. This happens because of the tremendous heat coming from the solar core. The solar interior below the photosphere (the convection zone) bubble s like a pot of boiling water. The bubbles of hot material welling up from below are seen at the photosphere, as slightly brighter regions. Darker regions occur where cooler plasma is sinking to the interior.
March 3, 1998Kristen (Wyoming, USA) As the Sun matures, what effect will it have on the Earth?In about 5 billion years, the Sun will start running out of fuel. When that happens, the Sun will start to collapse, getting hotter and hotter, then expanding again. It will then be called a red giant. When this happens, the Earth will probably be engulfed by the Sun, and certainly charred to a cinder. But there's quite a bit of time left before we need to worry about it!
February 12, 1998Alberto (Spain)Could you tell me anything about the North Atlantic Anomaly in the Earth's magnetosphere?The Earth's magnetosphere has regions of unusually high radiation. These regions are called the Van Allen Belts. You can think of them (in a loose sense!) as concentric rings of trapped radiation. Because of the way that the Earth's magnetic field is offset from its rotational axis, the Van Allen Radiation Belts come closest to the Earth's surface over the South Atlantic ocean. This area is referred to as the South Atlantic Anomaly (SAA). Astronauts/Cosmonauts in spacecraft try to avoid this area of the magnetosphere because radiation is so intense. Anyhow, you'd think there would be a corresponding anomaly (area of intense radiation) in the Northern hemisphere...but because of the offset of the magnetic axis with respect to the rotational axis, there is no symmetry involved.
February 6, 1998Damon (California, USA)If our sun were surrounded by a bright nebula, would we see it at night as an aurora-type phenomena?Let's look at how the aurora are formed. Charged particles from the Sun (if they get near enough) can get trapped in the Earth's magnetic field. These particles spiral down the Earth's magnetic field lines until they run into atmospheric gases. These collisions give off energy that we perceive as different colored light. So, it seems reasonable to say that if there were more charged particles surrounding/leaving the Sun (in the nebula you described), we'd have an increase in the aurora we see!
January 6, 1998Steve (Maine, USA)What is a sundog?Also called mock suns or parhelia, sun dogs are bright spots which appear on either side of the Sun when it is near the horizon. They are caused by ice crystals in the upper atmosphere which refract light in a certain way. Sun dogs usually appear 22 degrees to either side of the Sun. Also, moon dogs can form at night the same way sun dogs form during the day.
January 5, 1998Scot (Georgia, USA)Do sunspots have any affect on the daily temperatures here on Earth?The studies that have been done so far indicate that the influence of sunspots on Earth's temperature is very small. The most we can say is that sunspots may have some influence on major storm cycles, but that is all.

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