Space News & Blog Articles

For about a century, scientists have known that the Universe is in a state of constant expansion. In honor of the scientists who definitively showed this, this expansion has come to be known as the Hubble Constant (or Hubble-Lemaitre Constant). Today, scientists use two main techniques to measure the rate of expansion: the Cosmic Microwave Background (CMB) and the Cosmic Distance Ladder. The former relies on redshift measurements of the CMB, the relic radiation left over from the Big Bang, while the latter relies on parallax and redshift measurements using variable stars and supernovae (aka "standard candles").

When most people think of a supernova, they're thinking of a Type II core-collapse supernova. These are massive stars that have reached the end of their time on the main sequence. They've used up their supply of hydrogen and continue fusing heavier elements until the star can't support its own mass. The core collapses and they explode, outshining their entire host galaxy for months.

On April 8th, 2024, people across the world witnessed a solar eclipse, a relatively rare event in which the Moon occults (blocks out) light from the Sun. To capture this event, volunteers at 143 observatories across the U.S. trained their equipment on it as part of NASA's Eclipse Megamovie citizen science project. The images they took were groundbreaking and provided some of the most detailed images to date of the Sun's corona. After nearly two years of production and editing, the Eclipse Megamovie team has released the dataset from this project.

Anyone familiar with the search for alien life will have heard of the “Goldilocks Zone” around a star. This is defined as the orbital band where the temperature is just right for liquid water to pool on a rocky planet’s surface - a good approximation for what we thought of as the early conditions for life on Earth. But what happens if that life doesn’t stay on an Earth analog? If they, like we, start to move towards their neighboring planets, the idea of a habitable zone becomes much more complicated. A new paper from Dr. Caleb Scharf of the NASA Ames Research Center, and one of the agency’s premier astrobiologists, tries to account for this possibility by introducing the framework of an Interplanetary Habitable Zone (IHZ).

It's strange that a dying star is at the heart of this glowing cloud of gas, ionizing it and lighting it up almost like a living structure, but that's Nature for you. An aging Wolf-Rayet star, which has exhausted its hydrogen core, illuminates the Cat's Eye Nebula from within. The star, catalogued as HD 164963, has suffered episodic mass loss as it ages. Each complex layer in the gaseous nebula represents one episode of mass loss driven by the star's extremely powerful winds.