# Is it physically possible for gravity to accelerate an object with mass to the speed of light? [duplicate]

Is it physically possible for an object to achieve the speed of light if it is in a gravitational field strong enough and the mass does not collide before it attains a velocity of $c$? It is true that the mass of the object approaches infinity as its speed approaches $c$, but maybe there could be an (almost) infinitely powerful gravitational field (increasing in strength as the mass speeds up) originating from a very long distance away, which could accelerate the mass to this impossible speed? I ask this because it appears that you would not need an infinite amount of fuel for taking the object to the speed of light.

## marked as duplicate by John Rennie gravity StackExchange.ready(function() { if (StackExchange.options.isMobile) return; $('.dupe-hammer-message-hover:not(.hover-bound)').each(function() { var$hover = $(this).addClass('hover-bound'),$msg = $hover.siblings('.dupe-hammer-message');$hover.hover( function() { $hover.showInfoMessage('', { messageElement:$msg.clone().show(), transient: false, position: { my: 'bottom left', at: 'top center', offsetTop: -7 }, dismissable: false, relativeToBody: true }); }, function() { StackExchange.helpers.removeMessages(); } ); }); }); Nov 26 '17 at 11:39

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