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Supernova-propelled white dwarf found zooming through Milky Way at 5 million mph
- mkempe 8y agoThat speed (5 million mph = 2,235,200 m/s) is not quite 1% of the speed of light (299,792,458 m/s). The article is about a large Gaia data release [1] not just the speed of one astronomical object. Maybe change the title (currently "Supernova-propelled white dwarf found zooming through Milky Way at 5 million mph "). [1] https://www.cosmos.esa.int/web/gaia/dr2 https://www.cosmos.esa.int/web/gaia/dr2
- Jadex1 8y agoBut is it the speed of dark?
- cetico 8y agoAnd I used to worry about asteroids.. Looking forward to the Hollywood movie in which heroes have to stop a STAR from hitting Earth.
- saagarjha 8y agoShort of moving Earth out of the way, there's not a whole lot you can do in that case…
- archgoon 8y agoThe mere presence of another star anywhere near earth would have catastrophic effects on the solar system. https://www.youtube.com/watch?v=2dJEhPYfJ5U https://www.youtube.com/watch?v=2dJEhPYfJ5U
- saagarjha 8y agoMy comment was meant as a poor attempt at humor of the impossibility of the task. You think Hollywood cares about the effects of the star's gravity? The only thing that matters is when the star collides with Earth.
- maxxxxx 8y agoThere is nothing you could do with any conceivable technology. Even if a star would just traverse through the solar system it would probably throw the planets out of their orbits which would also be quite unpleasant.
- Simon_says 8y agoEvacuation involves conceivable technology.
- cfadvan 8y agoConceivable, but not remotely available at the moment, or on the horizon. Not to mention, evacuation to where? The whole solar system would be thrown into disarray, and we don’t know of any Earth-like planets in other systems. We’d be toast, end of story. Maybe in a few hundred years, and given a lot of warning we could save some small fraction of humanity.
- weberc2 8y agoShotgun approach: anywhere we think we might have even a remote hope of colonizing, prioritized and weighted (in terms of number of passengers) by likelihood of success. It's amusing to think on two such populations of this human diaspora surviving to eventually reunite one day, probably tens of thousands of years after the original colonization event faded from their collective cultural memories.
- noonespecial 8y agoReunite? Knowing humans they'd likely battle to mutual annihilation because their toenails were different colors. One would hope having one's solar system murdered by a rouge star might help a species grow up but right now I'm skeptical.
- mapmap 8y agoThis was a Star Trek plot that helped explain why most of the aliens were humanoid. https://en.wikipedia.org/wiki/The_Chase_(Star_Trek:_The_Next_Generation) https://en.wikipedia.org/wiki/The_Chase_(Star_Trek:_The_Next...
- lewis500 8y agoArmageddon 2: Starmageddon. Bruce Willis has to land on the surface of a star, drill down into it and release a hydrogen bomb. The fusion reaction will cause the star to blow up even though it’s already full of fusion. He’ll wear a suit made out of diamonds and have a spaceship made of diamonds, and an Aerosmith rendition of twinkle twinkle little star will play as the star explodes and diamonds rain from the sky. Now seeking story credit for this script.
- MisterTea 8y agoAlready stole the idea and have the rights secured. All the best, - Hollywood
- heavenlyblue 8y agoCodename: Brucy in the Sky of Diamonds.
- realPubkey 8y agoBut.. but diamonds are made of carbon and so can burn.
- sarkhan 8y agoYour script is missing how Bruce managed to escape exploding asteroid.
- StaticRedux 8y agoThe explosion propelled him through the Milky Way at 5 million miles an hour until he came back around to earth.
- AmericanChopper 8y agoI find the idea of a stat zooming through the Milky Way to be so hilarious, but I can’t really explain why. Stars just aren’t supposed to be going on high-speed solo adventures through the galaxy in my mind. Although perhaps a better movie would be about a black hole hurtling towards earth, as they’re also supposed to be traversing the galaxy.
- tux1968 8y agoAll stars are zooming through the Milky Way. :) The Sun does a full orbit in 225 to 250 million years. Although I have no idea why we can't calculate it more precisely than that.
- ifAndOnlyIf 8y agoWhen things really get going with outer space civilizations, the idea of weaponry and conflict is going to take some surprising and horrifying turns. We bicker about islands and aircraft carriers, nuclear arsenals and orbital ballistics, and something like this would rend the entire planet limb from limb in the blink of an eye, without breaking a sweat.
- dvirsky 8y agoYou should read The Three Body Problem trilogy for some interesting ideas in that direction.
- cfadvan 8y agoManipulating a white dwarf to kill a planet is like using a hydrogen bomb to kill an ant.
- wavefunction 8y agoImagine what that bad boy would do to perturb an entire solar system by even a near pass, though..
- ifAndOnlyIf 8y agoGiven that a typical white dwarf is thought to occupy a volume comparable to the volume of earth-like planets, it strikes me as precisely the sort of object one might select to destroy a planet like earth in a single stroke. From wikipedia: The estimated radii of observed white dwarfs are typically between 0.8% and 2% of the radius of the Sun; this is comparable to the Earth's radius of approximately 0.9% solar radius. https://en.wikipedia.org/wiki/White_dwarf https://en.wikipedia.org/wiki/White_dwarf Catapults, naval cannons, carpet bombing cities to hit one obscure factory. War is littered with stories of absurd mismatches in economies of scale.
- cfadvan 8y agoThe problem is while it has a volume comparable to Earth, its mass is comparable to Sol! It would take an unbelievable amount of energy to move something so massive from its original position to a collision course with another body. With a fraction of that energy you could pummel a planet with a swarm of tens of thousands of giant asteroids for years.
- phyzome 8y agoMy intuition is having trouble coming to grips with the notion of accelerating a fluid object to that velocity via an explosion.
- iaw 8y agoIt's because your intuition is on a human scales. White dwarfs apparently have a density near 1 tonne/cubic centimeter and consist of plasma which only runs analogous to fluids so far before the analogy breaks down. One difference is that plasma will have mobile charge carriers likely imparting something similar to a London dispersion force if there's any charge directionality in the super nova blast wave. What likely has the most impact though is the density and gravity that holds the object together in a way fluid droplets on earth do not.
- autocorr 8y agoSince white dwarfs have around the mass of the sun in a size comparable to the Earth, the matter in them is quite exotic. Astronomer's have speculated that these hypervelocity stars (moving at a few tenths of a percent the speed of light in the referenced studies case[1]) are shot out like a slingshot. The original system is a binary, so they are already under extreme circular gravitational acceleration in their orbit. When the companion explodes in a core-collapse supernova, it loses that source of acceleration and moves in a straight line like a slingshot. The Gaia satellite is able to measure the velocity vector of the star very well, and show that it points back to an old supernova remnant. The scenario isn't controversial, but it does give quite a good example that this is how they come about.
- Steel_Phoenix 8y agoThis makes me wonder about the nature of gravity. How much of the gravitational pull from the companion would disappear? How fast? It seems like a reduction in gravity would be immediately followed by a massive energy release. It's impressive that the remaining star is moving away fast enough to avoid being destroyed in the resulting blast.
- 8y ago
- nabla9 8y agoThat's 972 km/s. Escape velocity from the milky way is 537 km/s. That star is leaving the milky way.
- placebo 8y ago2235.2 km/s
- deleted 8y ago[deleted]
- iaw 8y agoI occasionally wonder about whether there are any objects out there traveling at a measurable fraction of c, could something even get through the atmosphere without disintegrating near those speeds?
- krapp 8y agoWould something moving that quickly and carrying that much energy be more likely to disintegrate in the atmosphere, or to disintegrate the atmosphere?
- pjc50 8y agoBoth, I suspect. At that speed, there's no point in talking about "flow" around it, it would simply compress all the atmosphere hit into a disc of plasma. The object would be disintegrated, but all the momentum has to transfer to the plasma disc instead. It would produce an impressive crater.
- jcims 8y agoRelativistic baseball explores some of that. https://what-if.xkcd.com/1/ https://what-if.xkcd.com/1/
- arrel 8y agoWhen they say 5 million mph, is that relative to the center of the Milky Way?
- CarVac 8y agoThis reminds me of black hole merger recoil, in which a merger emits a gravitational wave with net linear momentum, sending the resulting black hole in the opposite direction at comparable speeds to this. https://en.wikipedia.org/wiki/Binary_black_hole#Black-hole_merger_recoil https://en.wikipedia.org/wiki/Binary_black_hole#Black-hole_m...
- hinkley 8y agoIt’s like the machine at a batting cage that shoots the baseballs.
- hoodoof 8y agoCould this have planets? Well not planets, but my question is more general - could a star moving this quickly have a planetary system - obviously this one would not if it got shot out of a supernova.
- hinkley 8y agoAnything it passed that had a delta-v of less than the escape velocity of the white dwarf will get hoovered up. But most of what it passed would just scatter like bowling pins.
- perl4ever 8y agoI wish people would put high speeds in terms of miles/sec or km/s, because I know what light speed is in both, and I have a vague idea of orbital/escape speeds as well.
- mannykannot 8y ago5,000,000 / 3,600 = 5,000 / 3.6 ~= 1,000 miles/sec.
- perl4ever 8y ago5000 / 3.6 = 2500 / 1.8 = 1250 / 0.9 ~= 1,250 miles/sec
- KindOne 8y ago5,000,000 MPH = 8,046,720 km/h = 0.007455824656 in light speed
- HyperTalk2 8y agoThe shared link immediately redirected me to a fake malware page upon loading for the first time. https://i.imgur.com/wOJ0b67.png https://i.imgur.com/wOJ0b67.png Please blacklist astronomy.com links from being shared on this site. Also, perhaps consider shadowbanning clayt6 because judging from his account history he's apparently only here to spam astronomy.com links.
- sriku 8y ago> ...the Gaia satellite – which precisely measured the positions, motions, colors, and luminosities of over a billion Milky Way stars ... Can any physicists here explain how the coordinate system is constructed here?
- Black-Plaid 8y agoThe article also talks about a black hole accreting at a rate of 1% every million years that is 'currently' 20 billion solar masses. It is 12 billion ly away, which means, if it really does continue getting 1% larger every million years it's actually ... 143,719,397,330,047,128,616,744,826,647,657,321,145,325,176,127,225,856 billion solar masses at this moment. (if the compound interest calculator is to be believed) I really hope that's not true.