Stories tagged red giant

Sep
15
2007

Red alert: Based on what they've seen at the star V 391, astronomers say there is a possibility that Earth could survive a red giant phase expansion of our Sun. (Photo courtesy of NASA)
Red alert: Based on what they've seen at the star V 391, astronomers say there is a possibility that Earth could survive a red giant phase expansion of our Sun. (Photo courtesy of NASA)
Not that any of us reading this have to really worry about this personally, but there’s new evidence that the Earth could be able to survive should our Sun start to balloon into a red giant. That’s estimated to happen in a few billion years.

Astronomers have found a planet in a similar position as Earth’s relative to its star that continues to exist as the star has become a red giant. The star in question, V 391, was much like our Sun, but as it aged, its core ran out of hydrogen. That triggered a reaction where it began to burn helium and its outer surface expanded out about 100 times wider. It’s believed the same thing will happen to our Sun in about 5 billion years.

The planet in question has about three times the mass of Jupiter and orbits V 391 at about the same distance as Mars is from our Sun. However, the red giant action of V 391 is considered highly unusual and may be just representative of 2 percent of the red giant actions that happen to stars. Astronomers are continuing to watch what’s happening there, but say that it’s too small of a data sample to project what will happen to Earth when the Sun go to a red giant phase. The common thinking is Mercury and Venus will be vaporized in a red giant transition of the Sun while Earth would be on the borderline of the safety zone.

Oct
02
2006


Pine Barrens Tree Frog: In this image the tympanum can be seen as the small round disk to the right of the eye. Image courtesy Bruce Means and the U.S. Fish and Wildlife Service.
Do frogs have ears?

Yes, they do, but they are different from the ears we have. Frogs do not have external ears, rather they have something called a tympanum. The tympanum are behind the eyes, and look like round disks. Some tympanum are easier to see than others. They receive sound waves for the frog just like the tympanic membrane (also known as the eardrum) does for us. Frogs not only use the tympanum to hear, but also use their lungs. The lungs help with hearing, and also protect the frog’s eardrums from the very loud noises frogs make by equalizing pressures between the inner and outer surfaces of the tympanum.

What does sublimation mean?

In physics, sublimation is the process by which a solid converts to a gas and bypasses a liquid stage in doing so. Have you ever seen dry ice? At room temperature, dry ice sublimates directly into a gas, skipping the liquid stage.

Where do Komodo Dragons live?

There are about 6,000 Komodo Dragons living in the wild. They live on the Lesser Sunda Islands in Indonesia.

What causes hiccups?

There are a variety of causes for hiccups, including eating too quickly, swallowing too much air, taking a cold drink while eating a hot meal, laughing, coughing, or drinking too much alcohol.

Hiccups are an involuntary spasm of the diaphragm, the large muscle that separates the chest cavity from the abdominal cavity. The sudden intake of air into the lungs is stopped by the glottis, which causes the “hic” sound.

Do you know how fast the Earth spins on its axis?

Well, if you figure the Earth does one full rotation on its axis about every 24 hours (23 hours, 56 minutes, and 04.09 seconds), and the Earth’s circumference is around 25,000 miles (24,901.55 miles), then it spins at roughly 1,040 miles per hour.

Illustration of the life-cycle of the Sun: Illustration courtesy Tablizer.
Illustration of the life-cycle of the Sun: Illustration courtesy Tablizer.Courtesy Tablizer
Will the sun explode?

No, but one day it will be large enough to push the Earth into a new orbit while eradicating the Earth’s atmosphere – but not for a long, long time. Our sun does not have enough mass to “go supernova” and explode. But, in about 5-6 billion years it will start becoming a red giant once it has used up its supply of hydrogen in its core and switched to fusing hydrogen in a shell outside of its core. While this is happening other processes will cause the sun to grow. Much, much later, the red dwarf will become a planetary nebula, and then a white dwarf. This is the standard stellar evolution for a star such as our sun.