The Perseverance rover has been on Mars for 5 years now.  This month, NASA told us that a rock sample taken from an ancient dry riverbed on Mars shows potential biosignatures--possible signs of former life!

A potential biosignature is a substance or structure that might have a biological origin, but more analysis is required to determine the presence or absence of life.  According to NASA, the rover came across the sample when it was "exploring the "Bright Angel" formation, a set of rocky outcrops on the northern and southern edges of Neretva Vallis, an ancient river valley measuring a quarter-mile (400 meters) wide that was carved by water rushing into Jezero Crater long ago."

Perseverance analyzed the sample and found that the formation is made of clay and silt, which, on Earth, are excellent preservers of ancient microbial life.  It is also rich in chemical compounds that could have provided energy to ancient microbes.

This is the closest we have ever come to finding life on Mars!

Happy first day of fall!  We love to celebrate all of the seasons with science.  In this blog, you'll find instructions for how to write a letter in invisible ink, make art (using science), and make some delicious fall treats!

Secret Messages With Invisible Ink
Materials:
Cardstock
Measuring spoons
3 cups or small bowls
Spoon
Q-tips or a brush
Old newspaper or cardboard
Paper towels
For method 1: Water, lemon, and an iron
For method 2: Baking soda, water, turmeric and rubbing alcohol

Method 1:
1. Squeeze the juice of half a lemon into a bowl.
2. Add half a teaspoon of water to the lemon juice and mix it.
3. Dip a Q-tip into the lemon juice solution.
4. Use the wet Q-tip to write your message on cardstock.  Rewet the Q-tip if necessary.  Be careful not to soak the paper.
5. Let the paper dry completely.
6. Set the iron to high.  Run the iron over the paper and watch your message appear!

Method 2:
1. Mix 1 tablespoon of baking soda with 1 tablespoon of water in a bowl.
2. In a different bowl, mix 1/2 teaspoon of turmeric with 3 tablespoons of rubbing alcohol.
3. Dip a Q-tip into the baking soda solution.
4. Use the wet Q-tip to write your message on cardstock.  Rewet the Q-tip if necessary.  Be careful not to soak the paper.
5. Let the paper dry completely.  If there is baking soda residue on the paper, remove it with a paper towel.
6. Dip a Q-tip or brush into the turmeric solution.  Paint the whole paper with the turmeric solution and watch your message appear!

Marbled Cards
Materials:
Two large plates
Shaving cream
Liquid food coloring (at least two different colors)
White printer paper or cardstock
Scissors
Spoon
Toothpick
Jumbo craft stick
Paper towels
Spray bottle
Water

Method:
1. Place the two plates next to each other.
2. Cut two letter-sized pieces of paper in half crosswise.  Then fold each in half, creating four cards.
3. Put shaving cream on the two plates and spread it around with your hands.  Create a layer with an area at least as large as your paper card and about half an inch thick.
4. Drop several drops of the first color of food coloring onto the shaving cream on both plates.  Repeat with any other colors you are using.
5. With the toothpick, gently swirl the colors in the shaving cream until you have created a design that you like.  Try not to overmix.
6. Use the spray bottle to spray water on top of the color pattern on one of the plates.  Use 5-10 pumps of water.  Allow the foam to sit for one minute.
7. Place your first card with the front facing down on top of the shaving cream design and press it gently so that the whole card is covered in shaving cream.
8. Repeat the process with the other card and plate.
9. Remove the cards from the shaving cream.  Scrape any remaining shaving cream from the cards using the craft stick or a paper towel.
10.  Let the cards dry.

Toffee Apples
(Caution: Boiling sugar is HOT!!!)
Ingredients:
8 large Granny Smith apples
3 cups of caster sugar (superfine sugar)
1/3 cup of water
1/4 cup of liquid glucose (or light corn syrup)
1 teaspoon of white vinegar
red food coloring

Directions:
1. Line a large baking sheet with parchment paper and set aside.
2. Wash the apples, remove the stems, and dry well.  Push in a thick skewer or popsicle stick.
3. Add the sugar, water, glucose, and vinegar to a large, heavy-based saucepan.  Cook over very low heat stirring constantly until the sugar completely dissolves.
4. Bring the syrup to a boil and put a candy thermometer on the side of the pan.  Boil until the mixture is at the hard crack stage (302 degrees F).  Use a pastry brush with a little water on it to brush down any sugar crystals that form on the sides.
5. Remove the pan from the heat and mix the food coloring in.  Let the bubbles subside.
6.  Carefully tip the saucepan on an angle and dip the apples, turning them a few times to coat them well.
7.  Cool the apples on the prepared baking sheet.
​
Spiced Apple Cider
Materials:
10 Apples
Spices-cinnamon sticks, cloves, nutmeg, and cardamon
Stove
Muslin cloth
Potato masher
Bowl

Directions:
1. Core the apples and cut into large chunks.
2. Place apple chunks in a large pot.  Cover with water and add a selection of spices.
3. Heat until the water starts to boil.  Simmer for about 10 minutes.
4. Use the potato masher to thoroughly squish the apples.
5. Place the muslin cloth over the bowl and carefully pour the apple mixture over the top.  The apple juice will drip through the muslin, leaving the pulp behind.
6. Gather up the ends of the muslin and squeeze the pulp over the bowl to extract all of the juice.
7. Discard the pulp and enjoy your cider!

When Yuri Gagarin, the first man to orbit the Earth, was on his way to the launchpad in 1961, he realized he was about to go into space with a full bladder.  So the bus made a quick pit stop so that he could get out and pee on the tire.  Ever since then, it's tradition for every space traveler flying from the Baikonur Cosmodrome in Kazakhstan to pee on the tire on their way to a launch.  You might consider this to be the first astronaut superstition, but it's hardly the last.

Before every launch from the Kennedy Space Center, astronauts eat a meal of steak, eggs, and cake, no matter the hour.  There is also a tradition of playing poker until the commander loses.  Astronauts typically bring a stuffed animal on their flight with them as well.  Not only is it considered lucky, but the fluffy little guys are a safe way to signal that gravity has shifted when they start floating around the cabin.

Other people involved in launches have their own traditions and superstitions.  Launchpad engineers believe it is bad luck for astronauts to see the rocket before launch day, and will go to great lengths to make sure it doesn't happen.  Before every mission, NASA engineers design a poster of the crew modeled after a favorite sci-fi movie.

Some astronauts lately have even taken to carrying a towel with them for good luck.  Whatever the superstition, just remember: don't panic!

Auroras, also known as the northern lights, are a visual display of an intricate dance of particles and magnetism between the Sun and the Earth.  Also known as space weather, auroras are colorful and dynamic.  They can occur when energetic particles from the Sun collide with atoms and molecules in the atmosphere.