Astronomy Picture of the Day 4-18-03

NASA ^ | 4-18-03 | Robert Nemiroff and Jerry Bonnell

[petuniasevan]

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2003 April 18

Double Eruptive Prominences
Credit: SOHO - EIT Consortium, ESA, NASA

Explanation: Lofted over the Sun on looping magnetic fields, large solar prominences are composed of relatively cool, dense plasma. When seen against the brilliant solar disk they appear as dark filaments, but these enormous magnetic structures are bright themselves when viewed against the blackness of space as they arc above the Sun's edge In a rare visual treat, these two solar prominences arising from the Sun's southern (lower) hemisphere were captured in extreme ultraviolet light by the EIT camera on board the space-based SOlar and Heliospheric Observatory (SOHO) on March 21. For scale, the pair of plasma loops stretch above the Sun to a height of about twenty times the diameter of planet Earth. In a matter of hours, these prominences apparently erupted away from the Sun's surface and may have been associated with a flare and coronal mass ejection.

[petuniasevan]

Vacation Announcement

I will be on vacation from June 2nd through June 9th.
If anyone would like to volunteer to post APOD during that time, please FReepmail me.
Otherwise the APOD will not be posted as I will be visiting relatives in California.

Go to the SOHO Exploring the Sun webpage and click on the graphic in the upper left corner titled "The Sun Now". This will bring up a page listing all near-real-time images. Enjoy!

Here is an active area of the Sun; the magnetic field causes hot gases to be suspended in loops. This dramatic image is courtesy of the TRACE satellite.

[petuniasevan]

[herewego]

great pic- enjoy vacation!!

[Jeff Chandler]

That looks just like Phoenix, AZ on a July afternoon.

[petuniasevan]

LOL!

Hubby poorman drives trucks for a living.
I rode with him for a while. He one day decided to park in a mall lot in Tempe. Arizona Mills, I think. Anyway, we parked in the blazing sun (115 or so), and went inside. He got an eye exam and new glasses, and so it was a couple of hours before we left.

We got out to the truck and were surprised to see that the trailer had sunk into the asphalt under the left-rear tandems. That's how hot it was.

Poorman quickly moved the truck to another part of the parking lot before doing his logbooks.

[Jeff Chandler]

Who does he drive for?

[petuniasevan]

He started out with C.R. England, then went to Chizek Transport, then spent several years with Fox-Midwest.

Now he spots trailers and does cross-town deliveries for Paper Transport. Usually in Appleton. But if they cut hours at the local warehouses he will be back spotting trailers for Paper in the Procter & Gamble yard in Green Bay.

[petuniasevan]

P.S. Back then he was with England.

[firewalk]

Good morning & thanks for the ping

[GodBlessRonaldReagan]

Great pic!

[trussell]

Beautiful pictures today petuniasevan (As usual).

Hope you enjoy your vacation!!

[BradyLS]

I still don't get how the sun can burn for so many billions of years.

[BradyLS]

Fantastic pics as always, Petuniasevan! Enjoy your well-deserved vacation!!!

[Joan912]

Thanks for the ping; I absolutely love any and all pics of the sun!

Have a great vacation! :)

[MozartLover]

Sun Bump

[petuniasevan]

It's not burning, as such. "Burning", or oxidation as it is more accurately called, is a chemical process which can be either

• The loss or removal of electrons from an atom, ion or molecule

  or

• The gain or addition of oxygen by an atom, molecule or ion.

  On the other hand, the Sun and all stars are huge balls of mostly hydrogen gas (with a little helium and a dusting of other elements). Oxidation does not come into play here. The core of a star is under extreme pressure and temperatures are in the tens of millions of degrees. This allows the process of nuclear fusion to take place there.

  Nuclear fusion is an atomic reaction in which many nuclei (the centers of atoms) combine together to make a larger one (which is a different element). The result of this process is the release of a lot of energy (the resultant nucleus is smaller in mass than the sum of the ones that made it; the difference in mass is converted into energy by the equation E=mc₂). Stars are powered by nuclear fusion, mostly converting hydrogen into helium. In the most common process, the proton-proton reaction, 4 hydrogen nuclei combine to form a single helium nucleus; about 0.3% of the original mass is converted into energy.

[BradyLS]

Thanks for the answer, Petuniasevan! I understand the process much better now.

[petuniasevan]

I forgot to mention - the nuclear fusion process is very efficient, and since it converts hydrogen to helium, it has a LOT of "fuel" to work with.

Even nuclear fission (breaking off protons and/or neutrons from heavy elements to form lighter elements) is much more efficient than oxidation. Various space probes such as the Voyagers, Galileo, Viking, ALSEP, and Cassini all have a little reactor onboard for charging the batteries for the various equipment onboard. Radioisotope Thermoelectric Generators (RTGs) are still functioning aboard even the Pioneers 10 and 11. No other systems (e.g., batteries, fuel cells, etc.) can meet these mission requirements.

The Sun burns several hundred million tons of hydrogen per second, converting it to helium by nuclear fusion. The total mass of the sun is 2 x 1033 grams, out of which a small fraction of it is be used for nuclear reactions. If you calculate the age of the Sun based on the amount of gas consumed per second, you will find that the Sun can live for about 10 billion years.

[petuniasevan]

2 x 1033 grams

Forgot the subscript! OOPS! That should be 2 x 10₃₃ grams!

[petuniasevan]

It's good to see someone showing an interest in the field and asking good questions. It shows that the thinking cap is on!

I just found an excellent site that is part of the Cornell University websystem. There you can "Ask an Astronomer": See questions and answers from others; even ask questions yourself about astronomy and the Universe.

Curious about Astronomy? Ask an Astronomer!