Universe
Most common type of star in the Milky Way?
Red dwarf stars
Red dwarf stars make up an estimated ¾ of all stars found in the Milky Way. The surface temperature of red dwarf stars is less than 4,000 Kelvin, and they have a very low luminosity and therefore cannot be easily seen. In fact, from Earth not one red dwarf star can be seen with the naked eye. Since they develop very slowly and are constant for trillions of years, there are actually no advanced stars of this type in our universe because our universe is too young!
How many planets are in the solar system?
Eight
The eight planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
Which spacecraft is farthest from Earth?
Voyager 1
Which planet is called the red planet?
Mars
Mars gets its nickname because its surface is covered in iron oxide, or rust. The iron reacts with oxygen in Mars's thin atmosphere, giving it the reddish color you see in the night sky.
What is a nebula?
A nebula is a cloud of gas and dust in space, and it's where stars are born.
Difference between a meteoroid, a meteor, and a meteorite?
It's all about location
A meteoroid is a small rocky object in space. When it enters Earth's atmosphere and burns up, making a streak of light, it's called a meteor or shooting star. If it survives and lands on Earth, it's a meteorite.
Smallest planet in the solar system?
Mercury
Mercury is only a bit bigger than Earth's Moon. With almost no atmosphere, its temperatures swing from 800°F (430°C) during the day to -290°F (-180°C) at night.
What manned mission has traveled farthest from Earth?
Apollo 13
248,655 miles. This was achieved during the Apollo 13 mission which launched on April 11, 1970. During the mission an oxygen tank exploded. The explosion forced the crew to abort its mission to land on the moon.
What is the largest moon in the solar system?
Ganymede
Ganymede orbits Jupiter and is even larger than Mercury. It's the only natural satellite in the solar system known to have its own magnetic field. NASA's Juno spacecraft has sent back some fascinating data about Ganymede in recent years.
What is a black hole?
A black hole forms when a massive star collapses under its own gravity and creates a region so dense that nothing can escape its pull. The edge where escape is impossible is called the event horizon.
From the outside, time near a black hole appears to slow down. From inside, it might speed up. Einstein's general relativity predicted this, and observations with instruments like the Hubble Space Telescope have confirmed it.
What type of galaxy is the most common in the universe?
Elliptical galaxies
Galaxies are categorized as elliptical, spiral, or irregular. There are at least two trillion galaxies in the universe. Each galaxy is bound by gravity and consists of stars, dust, interstellar gas, and dark matter. They range in size from a few billion stars to one hundred trillion stars. The oldest and most distant observed galaxy is actually 32 billion light years from Earth and is located in the constellation Ursa Major.
What is the most famous comet and how often can it be seen from Earth?
Halley's Comet
It returns about every 75–76 years, so most people only get to see it once in their lifetime. The next time it will be visible is July of 2061.
Which NASA space flight was the last manned mission to the moon?
Apollo 17
Apollo 17 launched on December 7, 1972 as the first night launch done by NASA. It was also the final mission of NASA’s Apollo program. Apollo 17 was the last time humans traveled beyond low Earth orbit. The mission also boasted that at the time it had the longest moon landing, largest lunar samples, longest time in orbit, and the longest total moonwalks.
What is the closest star to Earth (after the sun)?
Proxima Centauri
After our Sun, called Sol, Proxima Centauri is the closest star at about 4.24 light-years away.
What is the Oort Cloud?
A distant shell of icy objects surrounding the solar system
The Oort Cloud is a huge, round region believed to stretch from about 2,000 to 100,000 astronomical units from the Sun, far beyond Neptune and Pluto.
What shape is the Milky Way?
A barred spiral
The Milky Way galaxy is a barred spiral, meaning it has a central bar-shaped area of stars with spiral arms extending outward. Our solar system is about 26,000 light-years away from the center.
What is the Earth's atmosphere made of?
Nitrogen (about 78%) and oxygen (about 21%)
Nitrogen makes up most of our air. The last 1% consists of argon, carbon dioxide, and other trace gases. Every day, Earth's atmosphere shields us from solar radiation.
What is the most recent telescope that was launched by NASA?
Nancy Grace Roman Space Telescope
It was launched Aug 30, 2026. This observatory will also be able to block starlight to directly see exoplanets and planet-forming disks, complete a statistical census of planetary systems in our galaxy, and settle essential questions in the areas of dark energy, exoplanets, and infrared astrophysics.
How many moons does Jupiter have?
67
Jupiter has the most moons in our solar system, followed by Saturn which has 62 moons. Mercury and Venus have no moons. Mars has 2. Uranus has 27 (possibly 29). And Neptune has 14.
What is a pulsar?
A rapidly spinning neutron star that emits beams of radiation.
A large star explodes (a supernova). After the explosion, its "heart" contracts into a very small but extremely dense object, a neutron star.
How big is the observable universe?
About 93 billion light-years in diameter
Beyond that, light from those areas hasn't reached us yet, so what's out there is still unknown.
What is the sun made of?
Mostly hydrogen and helium
The Sun is a huge ball of plasma, made up of about 73% hydrogen and 25% helium, with small amounts of heavier elements.
What was the first human-made object in space?
Bumper-WAC
In 1949, the “Bumper-WAC” became the first human-made object to enter space as it climbed to an altitude of 393 kilometers (244 miles). The rocket consisted of a JPL WAC Corporal missile sitting atop a German-made V-2 rocket. The V-2 was developed by Wernher von Braun’s team of German researchers, who surrendered to the United States at the end of World War II.
What is the largest crater on our moon called?
The South Pole-Aitken basin
It is an impact crater that is the largest, deepest, and oldest crater on the moon. The South Pole-Aitken basin is also the largest known crater in our Solar System. The crater is 1,600 miles in diameter and 8.1 miles deep in some areas.
What is dark matter?
Dark matter is something we can't see or feel. But we know it exists because we see the effect: galaxies are spinning faster than they should. It's as if there's another "something" there that's adding gravity.
Dark matter makes up about 27% of the universe. Dark energy, which is an even stranger force that drives the universe's expansion, accounts for about 68%. Everything we can see and measure is only about 5%. Most of the universe is still a mystery to us.