Showing posts with label Venus. Show all posts
Showing posts with label Venus. Show all posts

November 24 - First Observation of a Transit of Venus

  Posted on November 24, 2021


This is an update of my post published on November 24, 2010:



Every once in a while, one of the planets gets between us and the Sun. These planets are too far away to cast a shadow on our planet or to block much of the sunlight—in other words, they don't eclipse the Sun like the Moon occasionally does. Instead, from our point of view, they appear as tiny black dots that travel across the disc of the Sun. This is called a transit.

Only two planets can be seen in transit across the Sun from the Earth. Do you know which ones they are?

.
.
.
ANSWER: Mercury and Venus are both closer to the Sun than we are here on Earth, so they are the only planets that can get between us and the Sun.



Anyway, Jeremiah Horrocks was an English astronomer. He was the only person known to have predicted the transit of Venus on this date in 1639, and he is one of only two to have observed and recorded it. (His friend William Crabtree was the other.)

You may be wondering how he—or anybody—could watch a transit across the blindingly bright Sun. Well, he focused the image of the Sun through a simple telescope onto a piece of cardboard. He then watched the not-so-bright image on the cardboard. People still make this simple kind of helioscope these days, although astronomers have of course figured out more sophisticated systems with which they study the Sun.

NOTE: Never look at the image of the Sun EVEN with a helioscope without adult supervision.


A Rare Treat!

Transits of Venus are very rare. They happen in pairs that are eight years apart—and these pairs are separated by around 100 years! The last two transits of Venus occurred in 2004 and 2012. For many of us, that will likely be the last of our lifetimes! The next transit will be in December, 2117.

Transits of Mercury are much more frequent. The last one was in 2019, and the next one will be in 2032.


Notice how much larger Venus's dark disk looks
against the brightness of the Sun (above),
compared to Mercury's teeny spot (below),












Tie One On Day in the U.S.

(Day before Thanksgiving in the U.S.)






Posted by at 1 comment:
Labels: , , , , , , , ,

October 19 - Mariner 5 Flies by Venus!

  Posted on October 19, 2021


This is an update of my post published on October 19, 2010:





During the 1960s, there was a Space Race, with Cold War enemies Soviet Union and United States trying to outdo each other in exploring the solar system.

At first, the USSR pulled ahead by being the first to successfully launch a rocket into Earth orbit (Sputnik 1 – 1957) and then by being the first to put a man in space (Yuri Gagarin on Vostok 1 – 1961). A few months after each of these Soviet successes, the US was able to match the feats with Explorer 1 (1958) and Alan Shepherd in a Mercury spaceship (1961).


Many Americans would say, however, that the US won the Space Race because of the daring manned moon landings and explorations. To this date, this feat has not been matched by astronauts from any other country.

But, you ask, what does all of this have to do with Venus?

The Soviet Union and America's space program, NASA, chose a wide variety of projects, including exploring nearby planets, during the time of the Space Race. These planetary flights were all unmanned, and many of them did not succeed for one reason or another. Launch failures and loss of contact (in the latter case, the fate of the spacecraft is often unknown) happened with some regularity. However, when a mission worked, the data gathered by the spacecraft is beamed home and enriches the scientific knowledge for the entire world.


Here are some of the flights deemed failures:
1961 
USSR Sputnik 7
USSR Venera 1
1962 
US Mariner 1
USSR Sputnik 19
USSR Sputnik 20
USSR Sputnik 21
1963 
USSR Cosmos 21
1964 
USSR Venera 1964A
USSR Venera 1964B
USSR Cosmos 27
USSR Zond 1
1965 
USSR Venera 2
USSR Venera 3
USSR Cosmos 96
USSR Venera 1965A

And to offset all that failure during that four-year period:

1962 
US Mariner 2

Finally, in 1967, both nations met with success in exploring Earth's nearest planet. On October 18, 1967, the Soviet Venera 4 became the first probe to analyze another planet from its surface. And the very next day, October 19, 1967, the United States' Mariner 5 did a successful fly-by. Both spacecraft were able to send back important data that tells us a lot more about our “sister planet.”

Sister planet??? Umm...


Not only is Venus the closest planet to the Earth, it is the closest planet to ours in size. That is why it is called Earth's sister planet.

But it's not very much like Earth in some pretty crucial ways.

Here is a picture of what it might look like on Venus. It's really, really hot.


REALLY hot!

Like 900 degrees Fahrenheit! (500 degrees Celsius). That's hot enough to melt lead, zinc, and some alloys of aluminum!

Venus's atmosphere is 90 times thicker than Earth's, with thick clouds of sulfuric acid! Yikes!

But maybe future humans will colonize the atmosphere of this hellish planet and live there? Check out this outrageous sounding idea in this article.


Here are some photos we've pieced together from missions to Venus:






Posted by at 1 comment:
Labels: , , , , , , ,

August 17 – Extraordinary Journeys Day

Posted on August 17, 2018

One thing you could do to
celebrate Extraordinary Journeys
Day is to read the Jules Verne
story collection!
The first spacecraft to transmit data from the surface of another planet - extraordinary!

The first ship to reach the North Pole - hard to do, because this was back when it was covered with ice!

The first balloon to cross the Atlantic Ocean. Would you want to cross an entire ocean - with a balloon??

On this date in 1970, Venera 7 was launched by the Soviet Union, heading toward Venus. It later became the first
spacecraft to land on another planet AND the first spacecraft to transmit data from another planet's surface.

This was not without problems. By design, the lander remained attached to the interplanetary bus as long as possible so that the bus could cool the lander during the journey through Venus's thick atmosphere. When the lander ejected and opened its parachute, the parachute apparently failed. The lander ended up falling to the surface much quicker than planned - and therefore it hit the surface much harder than planned. 

The moment of impact, the spacecraft seemed to go silent. But, luckily, the recording tapes here on Earth still turned...just in case...A few weeks later, scientists reviewing the tapes discovered that there was a very weak signal, after all. The best guess is that the lander had bounced onto its side and left the antennae at the wrong angle to send a strong signal back to Earth.

Still, the weak signal told us that the lander had survived. And that the temperature on the surface of Venus was 475 degrees Celsius - that's 887 degrees Fahrenheit! - and THAT meant that there could be no liquid water on Venus, and that humans couldn't survive there.

This is an artist's idea of what the surface of Venus looks like.
Notice that it's hot-hot-hot!

So none of this:
Above and two below:
Back in the day, people imagined that
there might be creatures, even people,
on Venus....



Another big Soviet coup happened on this date in 1977, when the nuclear-powered icebreaker Arktika became the first surface ship to reach the North Pole.


The sudden, scary melting of Arctic sea ice has
scientists concerned. We need to work on reducing
global warming!!
The last extraordinary journey was completed on this date in 1978. This time, it was Americans daring to dare: three men piloted their balloon Double Eagle II from Maine to France. This first-ever balloon crossing of the Atlantic Ocean took a bit more than 137 hours!





The day before, on August 16, the men had had to give up their plans of hang gliding during the last bit of descent, because they had to drop the hang glider as ballast! Later, they crossed the Irish coast - and that right there made them the first to successfully cross the ocean in a balloon, even though they hadn't yet successfully landed! People at the Shannon Airport alerted the Double Eagle crew that they'd been spotted, but the balloonists continued on to France. 

Once there, authorities closed LeBourget Airfield so that the balloon could safely land there, and they radioed the crew with that offer. And that was a really nice offer - that's the place where Charles Lindbergh landed after his first solo transatlantic flight! But the balloon pilots knew that trying to make it all the way to that historic airfield would put them and others on the ground in danger. They were running out of ballast; they played it safe and landed in a field of barley near Miserey, rather than trying to make it to Paris.








Posted by at No comments:
Labels: , , , , , , , , , ,
Subscribe to: Posts (Atom)