Stories tagged astronomy

Feb
17
2008

Stranded Columbus crew starving in Jamaica

Lunar eclipse Feb 20, 2008
Lunar eclipse Feb 20, 2008Courtesy NASA Kennedy Space Center
Christopher Columbus sailed to the "New World" several times after his 1492 voyage. On his fourth and last journey ship worms so decimated his four ships that Columbus had to put ashore on the North coast of Jamaica and wait for rescue. Initially, the Jamaican natives welcomed the castaways, providing them with food and shelter in exchange for trinkets and whistles. When the natives no longer wished to provide food after more than six months, half of Columbus' crew mutinied, robbing and murdering some of the natives. With famine now threatening, Columbus formulated a desperate, albeit ingenious plan.

A bad moon is going to rise

Columbus, like all good sailors, had an almanac containing astronomical tables providing detailed information about the sun, moon and planets. Using its tables, Columbus calculated that on the evening of Thursday, Feb. 29, 1504, a total eclipse of the moon would take place soon after the time of moonrise. Three days before the eclipse Columbus told the chief that

his Christian god was angry with his people for no longer supplying Columbus and his men with food. Therefore, he was about to provide a clear sign of his displeasure: Three nights hence, he would all but obliterate the rising full moon, making it appear "inflamed with wrath," which would signify the evils that would soon be inflicted upon all of them.

According to Columbus's son, Ferdinand, when the moon started to eclipse, the natives ". . . with great howling and lamentation came running from every direction to the ships laden with provisions, praying to the Admiral to intercede with his god on their behalf." Just moments before the end of the total phase Columbus reappeared, announcing to the natives that his god had pardoned them and would now allow the moon to gradually return. Columbus and his men were well supplied and well fed until a relief caravel from Hispaniola finally arrived on June 29, 1504.

Total Lunar eclipse Wed. Feb 20 from 9-10 p.m. CST

Click this for information on when the lunar eclipse occurs around the world.The moon will start entering Earth's shadow at 7:43 pm CST Wednesday. Click this next link for an explanation of how and why you see the moon colored blood red, bright orange, or even a gentle turquoise.
Source: Space.com

Look up

by Liza on Dec. 13th, 2007

Hey, don't forget: The Geminid meteor shower, which you should be able to see this entire week, peaks tonight. Go out sometime between 10pm and dawn tomorrow, and look up. Let us know if you see any. Or get any photos.

Nov
30
2007

Where's the lightning?: I can't see any lightning in this picture, but recent magnetic antenna data shows that Venus has regular lightning flashes in its dense atmosphere.
Where's the lightning?: I can't see any lightning in this picture, but recent magnetic antenna data shows that Venus has regular lightning flashes in its dense atmosphere.Courtesy NASA
With a name like Thor, any mention of lightning and thunder jumps off the page (or computer screen) demanding my immediate attention.

So I was locked into yesterday’s account that the European Space Agency’s Venus Express has confirmed the theories astronomers have had for years, that lightning strikes on Venus.

Lightning is one of the factors considered in the evoluntionary process that could have “sparked” life into inorganic materials. But weather and climate conditions on Venus today suggest that the window of supporting life forms has been long shut on the planet.

But the finding of lightning has electrified the weather forecasts for Earth’s solar system neighbor. Previously, astronomical meteorologists had figured that Venus had a long, boring forecast of strong, steady winds for the next 400 years.

Venus Express, which has been orbiting Venus for nearly two years now, used a magnetic antenna to pick up the planet’s lightning activities.

So if you had a strong enough telescope to see a lightning flash on Venus, how long would you have to count until you hear the ensuing thunder clap? Talk amongst yourselves to come up with the answer.

Nov
25
2007

This is how the moon feels: all the time now.
This is how the moon feels: all the time now.Courtesy Wikimedia commons
The product of a brief and fateful union between the earth and “a body as big as Mars” in the back alley of the solar system, our moon has never quite come to grips with its lack of a present father figure With a distant mother and no siblings, the Moon has no true peers to turn to, and has always had to reassure itself that, someday, definitely someday, it would find a moon just like it, a friend and comrade that it could finally relate to.

Unfortunately, the social workers of the galaxy, astronomers, have recently had to bear the bleak news to the Moon that it is, at best, an ”uncommon moon”, and that the chances of it ever finding its soul mate are “pretty sucky.”

Most moons were either formed simultaneously to the formation of their planets, or were trapped by a planet’s gravity at some point. Our moon was probably created thirty to fifty million years after the formation of the solar system by a massive impact between Earth and a Mars-sized body (the impact would have tossed enough material into “circumterrestrial orbit” to form the Moon). These sort of moon-creating knock-ups, if you will, leave a cloud of telltale dust in a star system, allowing scientists a general idea of which moons were created that way. By examining how many star systems have this dust could, astronomers have determined that it is likely that only 5 to 10 percent of moons (at most) share a similar origin to ours.

This was an understandably crushing revelation for the Moon. It remains in a gray mood, despite the consolations of people around the world, many of who have insisted that it is “still pretty.”

A white dwarf: Actually, the white dwarf is the little dot down and to the left.
A white dwarf: Actually, the white dwarf is the little dot down and to the left.Courtesy The Hubble spacecraft
Scientists in New Mexico have recently discovered a new type of white dwarf in our galaxy. White dwarfs are essentially dying stars - larger stars, when they run out of fuel, collapse on themselves to become black holes or neutron stars, but smaller stars (like our sun) generally become white dwarfs, and continue to radiate heat for billions of years. Most white dwarfs have hydrogen or helium-rich atmospheres, but the recently discovered stars have carbon-rich atmospheres. The discovery may change our understanding of the evolution and death of stars.

Exciting news, certainly, but these "new" stars could never replace my all time favorite white dwarf. Seriously.

Nov
12
2007

Planet Waterslide: A digital reconstruction of "the most fun planet."
Planet Waterslide: A digital reconstruction of "the most fun planet."Courtesy **Mary**
There was a brief period in the history of the solar system about 3.9 billion years ago characterized by wayward space particles pelting the inner planets. The period is referred to as the Late Heavy Bombardment, and the moon still bears the crater scars of the repeated impacts (Earth was similarly battered, but the constant recycling of the crust has erased the craters).

The prevailing theory behind the LHB has long been that early reshuffling of the planets was responsible – specifically that a rebellious young Neptune moved further out from the sun (perhaps seeking a place of its own) and disturbed rocky bodies in the Kuiper Belt, causing them to “veer into the inner solar system.”

Recently, an astrophysicist at the Carnegie Institution in Washington DC has provided compelling evidence that a migrating Neptune may not have been the cause after all. He thinks that the impact craters on the moon more closely match asteroids from the Asteroid Belt just beyond Mars, and that these asteroids were sent there by a disturbed orbit of a fifth rocky planet (the other rocky planets being, of course, Mercury, Venus, Earth, and Mars).

The planet, dubbed Planet V, would probably have been bigger than the moon, but slightly smaller than Mars. The Carnegie scientist even developed a computer model detailing how Mars’ gravity could have upset V’s orbit, causing it to fall into the sun, passing through the Asteroid Belt and scattering asteroids on its way.

The theory obviously requires extensive testing before it can be accepted with any confidence, but, so far, it has passed the test of whether or not I like it. I do like it.

I’m not terribly attached to the name, though. “V” is okay, I supposed, but it’s been done. I was thinking that something along the lines of “Planet Waterslide” would be better, not only because it sounds fun, but because it more accurately describes the character of the planet as suggested by my own theories. See, I predict that further research will reveal that “V” was covered in waterslides, and inhabited solely by kittens and friendly dinosaurs (neither of whom, ironically, ever used the waterslides). Planet Waterslide was the destiny of mankind, the universe’s reward for our inevitable achievement of interplanetary travel. Unfortunately, jealous Mars, not as brave as his big brother Neptune, and who never moved out of the parents’ basement of the solar system, tricked, or possibly tripped, its little brother Waterslide.

From this point, the Carnegie theory pretty much takes over. Except that the asteroid craters on the moon, should they receive further study, will no doubt prove to be interspersed with much smaller, fluffier craters.

Oct
05
2007

Hot spot: The south pole of Neptune is warmer than the rest of the planet, at least right now, because its orbit is so large and slow. That portion of the planet has summer for 40 years. (Photo courtesy of NASA)
Hot spot: The south pole of Neptune is warmer than the rest of the planet, at least right now, because its orbit is so large and slow. That portion of the planet has summer for 40 years. (Photo courtesy of NASA)
Here on Earth, our coldest spots are on the poles. But go to Neptune and you’re singing a whole new tune.

Scientists have found that one of the coldest planets in our solar system has an unusual hot spot: its south pole. But don’t break out the sunscreen, swimsuits and sunglasses too fast.

Temperatures at Neptune’s south pole are about 18 degrees warmer than any other part of the planet, but the average temperature on the planet is 320 degrees below zero. And you thought Minnesota winters are harsh. An international team of astronmers just announced their temperature findings from the planet.

So why the difference?

Neptune’s south pole has been receiving summer sunlight for about 40 years. It’s mostly a function of how slow seasons change in a planet orbiting so far from the sun.

The planet is 2.8 billion miles from the sun. One Neptune year -- the time that it takes to make one complete orbit of the sun – is about 165 Earth years. Currently it’s south pole is in position for the perpetual sunshine, but that will all change in another 80 years or so, when the pole is in its winter position.

The frigid temperatures are the result of the Neptune getting just 1/900th the amount of sunlight that hits the Earth. So you probably can leave the sunscreen at home if you ever head that way.

Sep
25
2007

Explore the universe

Google Sky
Google Sky
Want to explore the universe? With views of 100 million stars and 200 million galaxies, Google Sky lets you be a virtual space traveler with just a few clicks of a mouse.

Download Google Earth

To get started on your own outer-space adventure, download the most recent version of Google Earth software. Select "Switch to Sky" under the "view" menu or click on the icon that I show with a red arrow.

You might need a guide

The Universe is a big place so you might get lost. For help, the column on the left offer lots of guided tours. Try the sightseeing link under places. The screen capture shows what I found by selecting "Supernovae and Exotic Stars" under the layers section. PCworld has created a file of Google Sky Placemarks. Download it and open it with Google Earth. In the left column, in the Places box, click the (+) next to "Spectacular Sights in Google Sky". These are like bookmarks (or stick pins) that take you to some fantastic places. One (A Dramatic Outburst - V838Mon) has a time line slider so you can see how the event changed over several years.

Have fun

Google sky incorporates high-resolution images from NASA's Hubble Space Telescope, the Space Telescope Science Institute, the Sloan Digital Sky Survey, and the Digital Sky Survey Consortium into a fun, interactive learning tool. I hope you can check it out (high speed internet required).

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.