Showing posts with label satellite. Show all posts
Showing posts with label satellite. Show all posts

March 13 - Look Up at the Night Sky!

Posted on March 13, 2021

This is an update of my post published March 13, 2010: 



Also: Citizen Science Opportunity!

Halley's Comet used to be feared as a message of doom. 

On this 
date in 607, Halley's comet reached its perihelion (the point when it is closest to the Sun). People feared comets back then, thinking they were messages of doom from the gods.

Uranus was discovered quite by accident!


On this date in 1781, Sir William Herschel accidentally discovered Uranus. When he first spotted it, through his telescope, he thought it was a star. However, each night as he watched, it moved against the backdrop of steady stars, so Herschel thought it was either a planet or a comet. Finally Herschel and other astronomers determined that it was indeed a planet, and Herschel got the honor of naming it.

He named it Geor
gium Sidus, or “Georgian Planet,” in honor of King George III of England. But astronomers outside of England didn't like the name, and some suggested going back to Roman gods, which were used to name the planets known since ancient times. (Uranus was the god of the sky.)


Pluto was predicted and searched for, because
astronomer Clyde Thombaugh noticed its influence
on the orbit of Neptune.


On this date in 1930
, Clyde Thombaugh announced his February 18th discovery of Pluto.

Apollo 9 splashdown!


On this date in 1969, Apollo 9 returned to Earth. This was a crucial step to getting men onto the moon, because it was the first manned flight with the Apollo lunar hardware and the first manned flight of the lunar module.


Explorer 43

On this date in 1971, an unmanned satellite called Explorer 43 was launched to study the region between Earth's atmosphere and the Moon.

People were looking for Hale-Bopp (above)
but got distracted by strange lights (below)


On this date in 1997, many people who lived in Phoenix, Arizona, went outside at night to spot the comet Hale-Bopp. However, they were distracted from their observation goal by a series of lights that immediately got dubbed “UFOs.”
Do you know what a UFO is?

If you guessed that it's an alien spaceship, sorry, you're w
rong. UFO stands for Unidentified Flying Object. When people say that they saw a UFO, it just means that they saw something in the sky and that they are not at all sure what that something was!

 

Notice that nobody saw anything REALLY strange!

In this case, a lot of people claimed that these particular UFOs were alien space-craft. However, we now know that they weren't alien spaceships. They aren't even UFOs anymore, because they have been positively identified: they were flares dropped from military planes. The flares had little parachutes and took a long time to drop—but they weren't flying, they weren't vehicles, and they certainly weren't vehicles for little green men!

So far in human history, we have never had any alien spaceships visit. (Rats!) Maybe that will happen some day, but it isn't very likely, because stars are REALLY far apart!

On this date in 2021, YOU will go out and look at the night sky. Won't you?

ALERT: This is the Citizen Science Opportunity I mentioned above!!




There is a p
rogram going on from now until March 14 (tomorrow) called the GLOBE at Night program. A lot of people all over the world are needed to go outside, find the constellation Orion, and compare the stars they see with a sky map. Then observers report to the GatN people, who will put together the data and find out how much light pollution there is in different parts of Earth. Even if you live in a big city with lots of lights, and so your night sky is pretty much washed out, the GatN people need your input!

To participate, check out the GLOBE at Night website.


By the way, GatN is a regular program that happens for two weeks in March every year. Last year alone, almost 30,000 observations were made by people from more than 100 different countries!


Learn more about Uranus.
The information is expressed very simply here. 
This site is better for older kids.

 



Take this quiz on Uranus!


1.The planet that Uranus most resembles is _______.

2.Uranus was the first planet discovered with a / an ____.
A. equation B. telescope C. human-made satellite

3. Uranus' weirdest feature is that it _____.
A. is lying on its side. B. has a really long oval-shaped orbit
C. is sometimes further away from the Sun than Neptune

4. True or False - Uranus has rings

5. The intensity of the Sun's light on Uranus is _____ that on Earth.
A. ½ B. ¼ C. 1/10 D. 1/400




ANSWERS: 
1. Neptune 
2. B - telescope
3. A - is lying on its side (Uranus probably got smacked by something really big a long time ago and got knocked “onto its side,” because it isn't revolving around the Sun while spinning like a top, like the other planets, but instead it is rolling around the sun like a bowling ball. Choices B and C are both false.) 
4.True - Uranus does have rings
5.D - 1/400



Also on this date:
























































K-9 Veterans Day







 Genealogy Day

 (Saturday of the first full week of March)







(Second Saturday in March)










Plan ahead:


Check out my Pinterest boards for:
And here are my Pinterest boards for: 

January 31 - First U.S. Satellite!

 Posted on January 31, 2021

This is an update of my post published on January 31, 2010:

Explorer 1


On this date in 1958, Explorer 1 was launched, becoming the first satellite launched by the United States.


The Soviet Union's successful launch of Sputnik 1 in October of 1957 shocked Americans, and the U.S. was in a hurry to match the feat. The Jupiter C rocket had already been developed, and Pasadena's Jet Propulsion Laboratory was directed to design and build the “payload” (the instruments or equipment) to be carried into Earth orbit by that rocket.


JPL completed the assigned jo
b in less than three months!

The main instrument aboard Explorer 1 was a cosmic ray detector. The experiment on this satellite and another one launched two months later led to the discovery of the belts of charged particles trapped by Earth's magnetic field, called the Van Allen Belts after the experiment's designer.


Van Allen belts

Explorer 1 made its last transmission back to Earth in May of the year it was launched, but it continued to circle the globe more than 58,000 times before orbital decay caused it to burn up in the atmosphere in 1970.


Orbital Decay (or, should our satellites be brushing longer and flossing more?)

When a satellite is in a low orbit around Earth, it may be slowed by “drag” from the Earth's atmosphere. This sets up a positive feedback loop:


The increased “drag” or friction from the atmosphere causes the satellite to reduce in speed.
Decreased speed causes the satellite to fall to a lower altitude above Earth.
A lower altitude means that the atmosphere the satellite encounters is denser (more molecules of gases per cubic foot).
The denser atmosphere causes even more friction.
Which causes even less speed.
Which causes an even greater fall in altitude.
Which means that the satellite is orbiting in even denser atmosphere.
And so on.
And so forth.

Eventually, the orbit is so low and the atmosphere so thick, the satellite encounters a lot of friction and burns up.

Orbital decay can affect, not only satellites, but also space stations, space shuttles, and even the Hubble telescope. The International Space Station regularly needs orbital boosts to fight against orbital decay.

International Space Station

Most satellites orbit our globe high enough that they encounter no atmospheric drag and therefore no orbital decay due to friction.



Instruments on Mars


JPL has had a lot of opportunity to design experiments for a variety of space exploration vehicles. In January 2010 we got some news about one of JPL's programs, the Mars Rover Program.

The bad news was that Spirit, one of the two rovers currently on Mars, had not been able to be UN-stuck from the soft sand that had trapped it since May 1, 2009. The scientists decided to stop attempting to move it but hoped that it would be able to do more science from its "stuck" position. (That didn't really happen, though; Spirit sent its last message to Earth in March, 2010.)


The good news was, Spirit and the Mars Rover Program had already been incredibly successful! As astronomer Phil Plait explained at his excellent blog “Bad Astronomy” (available here on Discover Magazine):


Spirit

Spirit and Opportunity “had a planned operational lifetime of 90 days. “That was in January 2004. “In other words, Spirit has been on Mars for over 2200 days, and even counting when it first got stuck, it still ran well for more than 20 times its nominal lifespan. Cars these days have a standard warranty for 7 years; how’d you like yours to run for 140 years?

So for me, while this news is not great, it has to be put in context: Spirit is one of the most successful NASA missions of all time. And its sister, Opportunity, is still running like a champ. I hope I’ll be doing as well when I’m 1400 years old.

Opportunity continued to function until mid-2018!!! That was about 55 times longer than its original hoped-for mission!!!

 

Opportunity


Experiments on Earth

  • Here is a hands-on experiment on the same topic.
  • NASA has a page for anyone who wants to spot the International Space Station in orbit.
  • Here's another NASA site. This one focuses on Mars, with games and other activities. Very fun!



Also on this date:









Street Children's Day