Measuring in Space
Equal to approximately 150 million kilometers, this standard unit of measurement is based on the average distance between Earth and the Sun.
What is an Astronomical Unit (AU)?
According to cosmic calendar scale models, our solar system and Sun formed this many years ago.
What is 4.6 billion years ago?
The initial factor that dictates the specific lifecycle path and final outcome of a star is its total amount of this.
What is mass?
This general term refers to any planet that orbits a star other than our Sun.
What are exoplanets?
Covering an area roughly the size of North America, this prominent reddish feature on Jupiter is actually a giant storm that has raged for centuries.
What is the great red spot?
This unit of distance, equal to approximately 12 trillion kilometers, is defined as the distance light travels through a vacuum in one Earth year.
What is a light year (ly)?
The Nebular Hypothesis begins with this cloud of dust and gas rich in heavy elements.
What is a nebula?
Stars maintain stability during their main stage by balancing the outward force of nuclear fusion against this inward force.
What is gravity?
This most common exoplanet detection technique relies on measuring the slight dimming of a star's light as a planet passes directly in front of it.
What is the transit method?
Named after the Roman goddess of love and beauty, this second planet from the Sun is the hottest planet in our solar system.
What is Venus?
This unit of distance is equal to about 3.26 light years and is defined by a parallax angle shift of one arcsecond.
What is a parsec?
During the formation of the Sun, extreme density and pressure triggered this process, fusing hydrogen protons and neutrons into helium.
What is nuclear fusion?
These massive stellar explosions are the only natural events in the universe powerful enough to create elements heavier than iron.
What are supernovas?
The Habitable Zone is defined as the orbital region around a star where temperatures allow for the presence of this critical substance.
What is liquid water?
In 1965, Alexei Leonov became the first human to perform this activity, spending 12 minutes tethered outside his Voskhod 2 spacecraft.
What is a space walk (or EVA)?
Discovered by Edwin Hubble in the 1920s, this phenomenon occurs when light from distant galaxies stretches to longer wavelengths as space expands.
What is redshift?
Gravity caused clumping in the protoplanetary disk, forming these intermediate rocky bodies that collided to become spherical planets.
What are planetesimals?
Formed after a massive star's supernova, just one teaspoon of this ultradense stellar remnant weighs 10 million tons.
What is a neutron star?
Scientists use this technique to analyze light passing through an exoplanet's atmosphere to detect chemical signs of life.
What is spectral analysis?
This boundary surrounding a black hole marks the point of no return, where gravity becomes so strong that not even light can escape.
What is the event horizon?
Because light takes time to travel vast cosmic distances, observing deep space means astronomers are effectively doing this.
What is looking back in time?
Remaining planetesimals left over from the Kuiper Belt and Oort Cloud form these icy objects, which grow dust and ion tails when approaching the Sun.
What are comets?
On an Hertzsprung-Russell (HR) diagram, stars spending the longest stable portion of their lives fusing hydrogen into helium sit along this region.
What is the main sequence?
Set to launch around 2040, this planned space observatory will analyze exoplanet atmospheres without needing them to be actively in transit.
What is the Habitable Worlds Observatory?
Orbiting Saturn, this massive moon is the only satellite in our solar system known to have a dense atmosphere and liquid lakes on its surface.
What is Titan?