STAR GAZER
THE INTERNATIONAL EDITION
Lorain County JVS NASA CORE / 15181 Route 58 South / 440/775-1400
/ FAX 440/775-1460 / nasaco@leeca.org / http://core.nasa.gov
Horkheimer: Greetings, greetings fellow star gazers. Have you ever wondered just why the stars change their position from hour to hour and from season to season? Well, wonder no more. O.K., we've got our skies set up for mid spring late April, early May, 9 p.m. your local time facing north where you will see the Big Dipper high above the North Star, which coincidentally is the end star of the handle of the Little Dipper. Now if our Earth were perfectly stationary in the heavens we would see these stars and all the other stars in the same place every single night. But because our Earth is not stationary but rotates from west to east on an imaginary line we call the Earth's axis the stars appear to slowly drift across the sky all night long in the opposite direction from east to west. Many call this the greatest optical illusion in nature because even though the stars look like they rise in the east, travel across the sky and set in the west, it is in fact, our Earth doing the moving. And if you look closely you will notice that all the stars appear to change their position and move from east to west except for one star, the North Star. The reason it does not move is because it is directly above our Earth's north pole, directly above our Earth's axis. So in effect it is like the hub of the great endlessly turning wheel of the heavens.
Now astronomers measure visual distances in the sky by degrees. The distance from a clear horizon to directly overhead, the zenith, is divided into 90 sections, 90 degrees. And 15 degrees is the distance all the stars move from east to west across the sky in one hour. So if the Big Dipper is in this position in mid spring at 9 p.m., it will be 15 degrees farther west one hour later and 15 more degrees west an hour after that. See for yourself using the Big Dipper or any pattern of stars, any hour of the night, any night of the year.
But there is one catch, if our Earth only rotated on its axis and didn't have any other motion we would see the same star patterns in the same places at the same times every night. The Big Dipper would be in the same place at 9 o'clock every night of the year. But such is not the case because in addition to our Earth's rotating on its axis once a day it also makes one journey around the Sun once a year. So as our Earth moves along in its orbit, it changes its position in respect to the stars a little bit each night with the result that if a given star rises just above the horizon at 9 p.m. one night, the following night that same star will rise 4 minutes earlier and will be approximately one degree farther along on its journey across the sky at 9 p.m. which further means that since every star rises 4 minutes earlier each night and is one degree farther along, after one month all the stars will be 30 degrees farther along their journey at 9 p.m. which further means that after 3 months, the length of a season, all the stars will have moved 90 degrees across the sky at 9 p.m. and thus we will see different stars at the same hour of the night each season.
Orion is high up in early evening winter so he is called a winter star pattern. Leo is always high up in early evening in spring, so we call Leo a spring star pattern. Scorpius is high up in summer, Pegasus the horse, high up in autumn. It's that simple. The stars move because #1 our Earth rotates on its axis and #2 because our Earth orbits the Sun. Keep looking up!
How did you like this episode?
Please give us your comments. (Click
Here)
Horkheimer: Why do the stars change their position from hour to hour and season to season? Well because our Earth rotates on its axis from west to east the stars appear to move across the sky from east to west about 15 degrees per hour. Plus because our Earth orbits the Sun all stars rise 4 minutes earlier each successive evening and are thus one degree farther on their journey at the same time each successive night or 90 degrees along in three months which is a season. Orion is high in winter so he is a winter star pattern, Leo is always high in the sky in early evening in spring. Scorpius in summer and Pegasus the horse rides high in autumn. Stars move because our Earth rotates on its axis and because our Earth orbits the Sun. Keep looking up!
How did you like this episode?
Please give us your comments. (Click
Here)
* This week's Sky At A Glance and
Planet Roundup from Sky & Telescope.
This week's Sky At A Glance displays current week only.
Starry Night Deluxe was used to produce this episode
of Star Gazer
Lorain County JVS NASA CORE / 15181 Route 58 South / 440/775-1400 / FAX 440/775-1460 / nasaco@leeca.org / http://core.nasa.gov
Horkheimer: Greetings, greetings fellow star gazers. Have you
ever wondered just what is a star anyway and how far away they
are? Well let me unwonder you. O.K. If we could go out any clear
night and look up at the stars could you point out the closest
one? Some people think it's the North Star but nothing could be
farther from the truth because you can't see the closest star
at night at all. You can see it only in the daytime. It's our
Sun.
Yes indeed our Sun is a star and it's the closest star to Earth. The only reason it doesn't look like the other stars at night is because it is so close. And the reason the other stars don't look like our Sun is because they are so incredibly much farther away. Now all the stars make their own light similar to the way our Sun does. You see our Sun and all the stars are gigantic balls of hot glowing gas. And most of them make their light by thermonuclear processes. Or if you like to think of it this way our Sun produces more energy every single second than several million hydrogen bombs detonating at the same time. So our Sun must be huge.
In fact it is 865,000 miles wide. Compare that to our tiny 8,000 mile wide Earth and if you do the math almost 1.3 million Earth's could fit inside our Sun. And believe it or not our Sun is just an average size star. There are many much larger. So when we look at the stars at night including the stars of the Big Dipper we are really seeing other Suns so far away that they look like tiny pinpoints of light. The planets are billions of times closer. And our Sun is extremely close to us starwise, only 93 million miles away. But when it comes to measuring the distance to other stars astronomers don't like to use the word miles because they'd have to use too many numbers.
Instead we measure the distance to the other stars using the fastest known thing in the universe, the speed of light. Light travels an incredible 186,000 miles a second so we never actually see our Sun and the other stars as they actually exist at the moment. We always see them as they existed some time in the past depending on how far away they are. We see our Sun as it existed 8 and a third minutes ago because it takes light that long to travel from the Sun to reach us. But the other stars are much farther away. So we use a term called the light year to measure distances to them. A light year is simply the amount of miles light travels in one year. Multiply all the seconds in one year times 186,000 miles per second and you'll see there are roughly 6 trillion miles in one light year and the closest star to Earth other than our Sun is Proxima Centauri 4.2 light years away. So we see it as it existed 4.2 years ago!
What about our old friend the North Star who
many people think is the closest? Well it's a whopping 431 light
years away, which means we see it as it existed 431 years ago.
And although it doesn't look very bright it is actually 1600 times
brighter and 67 times wider than our Sun! Wow! Star light, star
bright, now we know what you are tonight. Keep looking up!
How did you like this episode?
Please give us your comments. (Click
Here)
Horkheimer: Have you ever wondered just what is a star any way? We can't see the closest star at night because it is our Sun and the reason the other stars at night don't look like our Sun is because they're so incredibly much farther away. All stars are gigantic balls of hot glowing gas and make their own light by thermonuclear processes. Our Sun is so huge we could fit 1.3 million earths inside it. And our Sun is just average! For instance even though the North Star doesn't look very bright because it's so far away is actually 1600 times brighter and 67 times wider than our Sun and there are many stars which are much larger. See our star in the daytime and the other stars at night. Keep looking up!
Please give us your comments. (Click
Here)
* This week's Sky At A Glance and
Planet Roundup from Sky & Telescope.Starry Night Deluxe was used to produce this episode
of Star GazerLorain County JVS NASA CORE / 15181 Route 58 South / 440/775-1400 / FAX 440/775-1460 / nasaco@leeca.org / http://core.nasa.gov
Horkheimer: Greetings, greetings fellow star gazers.
As I alerted you earlier this month one of the most spectacular
super close meetings of the planets you'll ever see will occur
this week and next. And in fact this Sunday and Monday the two
planets closest to the Sun won't be this close again until the
year 2070. Let me show you.
O.K., we've got our skies set up for earlier this month Sunday June 12th facing west north west thirty to 45 minutes after sunset while there is still twilight out where you would have seen the brightest planet of them all, planet #2 from the Sun Venus and planet #1 from the Sun, Mercury, peeking just above the horizon. And on a straight line with Mercury and Venus up to their left planet #6 ringed Saturn. And if you watched night after night you would have seen all three of them steadily move closer and closer to each other, Saturn descending and Mercury ascending to meet brilliant Venus.
But this week the changes from are really dramatic, Monday the 20th, Wednesday the 22nd and then the super planet show begins because starting Friday the 24th and lasting for three nights Mercury, Venus and Saturn will be only two degrees apart from each other. On Saturday the three are at their absolute closest to each other and could fit in a circle only one and a half degrees wide, so close you could cover all three with your pinky finger held out at arms length. But the best is yet to come because on Sunday the 26th Mercury and Venus will be less than one half of one degree apart. And to top that on Monday the 27th they'll be only one tenth of one degree apart, at their closest until 2070! So close that the Old Farmer's Almanac claims they may even appear to merge into one star. Wow! Once again this Friday, Saturday and Sunday Mercury, Venus and Saturn will form a super close trio and on Monday you won't see Mercury and Venus this close for another 65 years!
Of course we must remind you that this is all an optical illusion and that they only appear close from our vantage point here on Earth. In reality on Monday when Mercury and Venus appear to almost merge Mercury will be 95 million miles away while Venus will be 142 million miles away and Saturn will be a whopping almost one billion miles away. Don't miss this super spectacular planetary gathering. Start watching this week but make sure that you don't miss this Friday, Saturday, Sunday and ta da! Monday. And if you've got a small telescope or binoculars, get them out now because the change from night to night will absolutely stun you. But don't fret if you miss this weekend because Mercury and Venus will still be really close all next week too! If you've never engaged in planet watching before this weekend is the time to start. I mean who wants to wait until 2070? Keep looking up!
How did you like this episode?
Please give us your comments. (Click
Here)
Horkheimer: One of the most super close meetings of the planets you'll ever see will occur this week and next. All week long Mercury and Saturn have been approaching Venus and this Friday, Saturday and Sunday will form a trio so close you could cover all three with your pinky finger. But even better on Sunday Mercury and Venus will be less than one half of one degree apart and on Monday only one tenth of one degree apart at their closest until 2070! So close the Old Farmer's Almanac claims they may even appear to merge into one star. Once again Friday, Saturday and Sunday the three form a super close trio and on Monday you won't see Mercury and Venus this close for another 65 years! I mean who wants to wait until 2070? Keep looking up!
How did you like this episode?
Please give us your comments. (Click
Here)
* This week's Sky At A Glance and
Planet Roundup from Sky & Telescope.Starry Night Deluxe was used to produce this episode
of Star GazerLorain County JVS NASA CORE / 15181 Route 58 South / 440/775-1400 / FAX 440/775-1460 / nasaco@leeca.org / http://core.nasa.gov
Horkheimer: Greetings, greetings fellow star gazers and mark the
first ten days of July as fantastic nights for planet gazing because
we'll have Mercury, Venus and Jupiter in a spectacular early evening
planet show! Let me show you. O.K., we've got our skies set up
for this weekend Friday July 1st about an hour after sunset during
evening twilight facing west where you'll still be able to see
the best planet duo of the year, planet #1 out from the sun, the
tiny 3.000 mile wide pink planet Mercury huddled right next to
the brightest planet of them all, planet #2, 8,000 mile wide Venus.
And they will be only one degree apart which means you could well
cover both of them with your pinky finger stretched at arm's length.
And in fact they were less than one degree apart all throughout the last days of June and will continue to be extremely close through the first week of July. And although they are absolutely fabulous to see with the naked eye I beg you that if you have a pair of binoculars use them this weekend and all next week because rarely do we have a chance to see any two planets so close together.
On Saturday they'll be only one and one tenth of a degree apart and on Sunday they'll be only one and a quarter degree apart. And ta da! on the night of the 4th before the fire works start make sure you see them because they'll still be only one and a third degree apart. On Tuesday the 5th they're still only one and a half degrees from each other, and on Wednesday still extremely close. Then on Thursday the 7th something new is added to the scene because they are joined by an exquisitely thin crescent Moon complete with earthshine which will look like a black full Moon nestled within the crescent.
Then for the most spectacular planetary sight you'll see throughout all of July on Friday the 8th an even more exquisite crescent Moon will be parked right above Venus and Mercury and will not only knock your socks off with just the naked eye but if you look at them through a pair of binoculars you won't believe it! By Saturday the 9th the Moon will have moved past Venus and Mercury and will be parked very close to Regulus the brightest star of Leo the Lion and by Sunday the 10th will have moved just beyond it. So start your Mercury, Venus watch this weekend and look for them before the fireworks on the 4th of July. Then continue watching each night. But remember that Friday the 8th is the best night of them all!
On Saturday the 9th the Moon is parked to the
right of Regulus and on Sunday the 10th up to its left. But please,
please don't miss Friday the 8th which I consider the best night
for planet gazing for all of July. And of course we don't want
to leave out the planet king Jupiter who will be well up and to
the left of Regulus although not quite as bright as Venus but
will still dazzle you with his brilliance. And if you want to
appear really smart on July 4th casually show your friends planet
#1, planet #2 and planet #5. Wow! What a way to begin the month
of July. Keep looking up!
How did you like this episode?
Please give us your comments. (Click
Here)
Horkheimer: Mark the first ten days of July
as fantastic nights for planet gazing. Go out every night just
after sunset starting this Friday and you'll see the closest meeting
of any two planets for the entire year, planet #1, 3000 mile wide
mercury and planet #2, 8,000 mile wide venus. For eight nights
they'll be so close you can cover them both with your pinky finger
stretched at arm's length. They'll change position only slightly
each night and on Friday the 8th will be joined by an exquisite
crescent Moon in a sight that will knock your socks off. In fact
Friday night is the best night of them all in July for planet
gazing and if you have a pair of binoculars this sight will take
your breath away. Don't miss this please. Keep looking up!
How did you like this episode?
Please give us your comments. (Click
Here)
* This week's Sky At A Glance and
Planet Roundup from Sky & Telescope.
This week's Sky At A Glance displays current week only
Starry Night Deluxe was used to produce this episode
of Star Gazer
![[SmilinJack]](jack1sm.jpg)
Return to the [STAR
GAZER Main Page]