As stars in the Milky Way move through space, some of them have an unexpected effect on the Solar System. Over time, one comes closer to the Sun during its orbit in the galaxy. Some of them actually get within a light-year of our star and pass through the Oort Cloud. Such close flybys can affect the orbits of the outer planets and send cometary nuclei on a long inward rush to the Sun.Continue reading “A Star Passed Through the Oort Cloud Less Than 500,000 Years Ago. It Wasn’t the Only One.”
By discovering two interstellar objects (ISOs), we know that asteroids and comets from other star systems pass through the Solar System from time to time. By inference, some of these must have crashed into the Moon, creating impact craters. If we could study the impact sites, we might be able to learn about the star systems that they came from.
A new paper suggests there could be a way to determine which lunar craters came from interstellar object impacts. The authors say that young, small craters with high-melt volume near the Moon’s equator are likely the best candidates for ISO-generated craters on the lunar surface.Continue reading “Some of the Moon's Craters are From Interstellar Impacts. Can We Tell Which?”
Comets are instantly recognizable by their tails of gas and dust. Most comets originate in the far, frozen reaches of our Solar System, and only visit the inner Solar System occasionally. But some are in the Main Asteroid Belt, mixed in with the debris left over after the Solar System formed.
Astronomers just found water vapour coming from one of them.Continue reading “JWST Finds a Comet Still Holding Onto Water in the Main Asteroid Belt”
The large impact craters dotting our planet are powerful reminders that asteroids and comets strike the Earth from time to time. As often said, it’s not a question of “if”; it’s a matter of “when” our planet will face an impending strike from space. But an impact is one existential threat humanity is finally starting to take seriously and wrap its head around.
Seemingly spurred by the success of the Double Asteroid Redirection Test (DART), NASA just released a new planetary defense strategy and action plan, describing its efforts to find and identify potentially hazardous objects to provide an advanced warning, and then even push them off an impact trajectory.
This 10-year strategy looks to advance efforts to protect the Earth from a devastating encounter with a Near Earth asteroid or comet.Continue reading “Here's How NASA is Planning to Protect Earth From Asteroids and Comets”
Nothing excites space enthusiasts like a good alien mystery. The interstellar visitor ‘Oumuamua presented one as it moved through the inner solar system in 2017. At least one scientist has insisted that this pancake-shaped object is an alien spacecraft. That’s because of the way it accelerated away from the Sun as it passed through. However, a number of planetary scientists say its activity might be more comet-like—something fairly common in the solar system.Continue reading “Why Does ‘Oumuamua Follow Such a Bizarre Orbit? Hydrogen Outgassing”
A rare ‘green’ comet is passing through our Solar System and astrophotographers have been out capturing photos. While this comet, named C/2022 E3 (ZTF) is not yet visible yet to the naked eye, it could be when it makes its closest approach to Earth on February 1, but you’ll likely need to be in a very dark site. As of now, you’ll need a telescope or binoculars to see it for yourself. The images here are taken with several minutes of exposure time.
This comet has been dubbed the “Green Comet” because of its greenish hue. Professor Paul Wiegert from Western University in Canada said that comets contain carbon-bearing molecules, which break down under ultraviolet light from the Sun. This produces, among other things, dicarbon molecules which produce the eerie green glow associated with some comets.
Our lead photo comes from photographer Chris Schur from Arizona, and he points out that the comet has a rare sun-ward pointing anti-tail.Continue reading “Spectacular Images of the Rare ‘Green Comet’ Gracing Our Skies”
Jupiter is the most-visited planet in the Solar System, thanks largely to NASA. It all started with Pioneer 10 and 11, followed by Voyager 1 and 2. Those were all flyby missions, and it wasn’t until 1996 that the Galileo spacecraft became the first to orbit the gas giant and even send a probe into its atmosphere. Then in 2016, the Juno spacecraft entered orbit around Jupiter and is still there today.
All of these missions were focused on Jupiter, but along the way, they gave us tantalizing hints of the icy moon Europa. The most impactful thing we’ve learned is that Europa, though frozen on the surface, holds an ocean under all that ice. And that warm, salty ocean might contain more water than all of Earth’s oceans combined.
Might it hold life?Continue reading “Comet Impacts Could Have Brought the Raw Ingredients for Life to Europa’s Ocean”
Here’s a thorny problem: What if life doesn’t always appear on planets that can support it? What if we find more and more exoplanets and determine that some of them are habitable? What if we also determine that life hasn’t appeared on them yet?
Could we send life-bringing comets to those planets and seed them with terrestrial life? And if we could do that, should we?Continue reading “We Could Spread Life to the Milky Way With Comets. But Should We?”
Comets are messy things. They scatter bits of dust as they travel through the solar system. If Earth happens to encounter one of those cometary dust trails, we get to see a meteor shower.Continue reading “Comets Leave Dusty Trails That Surround the Solar System”
Comets that venture close to the Sun can transform into something beautiful, but sometimes they encounter incineration if they get too close. Of the various types of comets that orbit close to the Sun, astronomers had never seen the destruction of the type classified as “near-Sun” comets. But thanks to a variety of telescopes on summit of Mauna Kea in Hawai?i, scientists have now captured images of a periodic rocky near-Sun comet breaking apart. They say the disintegration of this comet could help explain the scarcity of such periodic near-Sun comets.Continue reading “Astronomers Watched a “Near-Sun” Comet Disintegrate as it Flew too Close to the Sun”