grobi<p>Where did this interstellar object come from?</p><p>3I/ATLAS formed in another star system and was somehow ejected into interstellar space, which is the space between the stars. For millions or even billions of years, it has drifted until it recently arrived at our solar system. It has been approaching from the general direction of the constellation Sagittarius, which is where the central region of our galaxy, the Milky Way, is located. When discovered, 3I/ATLAS was about 410 million miles (670 million kilometers) away from the Sun, within the orbit of Jupiter.</p><p>How was it determined that 3I/ATLAS didn’t originate in our solar system?</p><p>Observations of the comet’s trajectory show that it is moving too fast to be bound by the Sun’s gravity and that it's on what is known as a hyperbolic trajectory. In other words, it does not follow a closed orbital path around the Sun. It is simply passing through our solar system and will continue its journey into interstellar space, never to be seen again.</p><p>How many interstellar objects have been discovered?</p><p>This is the third known interstellar object to have been observed. Discovered in 2017, ‘Oumuamua was the first known interstellar object; the second was 2I/Borisov, which was discovered in 2019.</p><p>How big is 3I/ATLAS, and is it an asteroid or comet?</p><p>Astronomers don’t yet know how big 3I/ATLAS is, but from observations, they can see that it’s active, which means it has an icy nucleus and coma (a bright cloud of gas and dust surrounding a comet as it approaches the Sun). This is why astronomers categorize it as a comet and not an asteroid.</p><p>How fast is it moving?</p><p>Very fast. When it was discovered, the interstellar comet was traveling about 137,000 miles per hour (221,000 kilometers per hour, or 61 kilometers per second), and its speed will increase as it approaches the Sun.</p><p>CREDIT:<br>ATLAS/University of Hawaii/NASA</p><p><a href="https://science.nasa.gov/solar-system/comets/3i-atlas/" rel="nofollow noopener" translate="no" target="_blank"><span class="invisible">https://</span><span class="ellipsis">science.nasa.gov/solar-system/</span><span class="invisible">comets/3i-atlas/</span></a></p><p><a href="https://defcon.social/tags/space" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>space</span></a> <a href="https://defcon.social/tags/comets" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>comets</span></a> <a href="https://defcon.social/tags/astrophotography" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>astrophotography</span></a> <a href="https://defcon.social/tags/photography" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>photography</span></a> <a href="https://defcon.social/tags/science" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>science</span></a> <a href="https://defcon.social/tags/astronomy" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>astronomy</span></a> <a href="https://defcon.social/tags/nature" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>nature</span></a> <a href="https://defcon.social/tags/NASA" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>NASA</span></a> <a href="https://defcon.social/tags/ESA" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>ESA</span></a></p>